Meet the folks behind three unique kitchen-table businesses that wouldn’t exist if it weren’t for the iPhone.

The U.S. economy is in the dumps, but you wouldn’t know it judging by how many iPhones Apple has sold in the last quarter. Besides enflaming major cases of techno-lust, the iPhone has also stimulated the launch of some rather idiosyncratic small businesses. Here we profile three small businesspeople whose goals range from philanthropy and community-building to providing a sarcastic soundtrack for life to fixing the iPhone 3G’s most glaring weakness. But they all have one thing in common: a compulsion to create cool products and establish going concerns.

Mike Lee, United Lemur (unitedlemur.org) 

The lemur thing started when Mike Lee bought the book Lords and Lemurs for his wife, who has a sweet spot for the big-eyed primates. After reading the book, Lee’s concern for the future of Madagascar’s unofficial mascot fused with an idea set forth in a speech by Barack Obama that was already knocking around in his head: “You are the change you’ve been waiting for.” Altruistic capitalism was the change Lee says he’d been waiting for, and so United Lemur was born.

Lee has plenty of business start-up experience, some not so rosy. He’s a cofounder of Tapulous (makers of popular iPhone apps Tap Tap Revenge and Twinkle), and until August 2008 was Tapulous’s chief architect of client software. He was forced out of the company, citing “irreconcilable differences” between his engineering and design team and company management in a post on his blog. He was, as he said, “the messenger who got killed.” Before founding Tapulous, Lee was a programmer with Monster Software in Seattle and was part of a team that won an Apple Design Award.

Mike Lee’s wife’s love of lemurs spurred his drive to help preserve the wildlife of Madagascar, among other philanthropic goals.

With a mission statement to “ship beautiful products to make a better world,” United Lemur develops iPhone apps and donates 10 percent of its App Store revenue to nonprofit organizations. Lee has also launched what is intended to be an alternative to the traditional startup-funding process: His program Fundware (fundware.info) enables developers to go straight to end users to raise money that they can use to develop kernel ideas into full-fledged businesses. Participating companies develop a small iPhone app that serves as an introduction to their work, then those who want to support the business, purchase the app to help fund the companies’ full-scale projects.

Lee says he believes that positive, creative work is a world-changer. “I don’t have a work life separate from other lives. I’m on the clock all the time. I wake up in binary-print pajamas and engineer some breakfast. My business teaches me a surprising amount about myself. It makes me a better person.”

United Lemur now has 10 employees and Lee says the business has “just crested that hill where we stop living on savings and start living on revenue.”

Of course, revenue is not his only concern. “I don’t think of success as a destination so much as a philosophy,” he says. “When I get email from Madagascar describing the good we’ve done, I consider the company successful. But I try not to dwell on success. The work is its own reward. We’re already on to the next cool idea.”

Brian Gorby, Tiny Violin (gorbster.net) 

When Apple opened the doors to independent developers to create iPhone apps, Brian Gorby felt compelled to try his hand at developing something. That something turned out to be an iPhone app that lets you express your, uh, heartfelt sympathy by playing sad violin riffs on your iPhone—just the thing to whip out when a relative or coworker is relating a sob-story excuse for being late to an important family gathering or staff meeting.

“The first week the iTunes App Store was open, I Googled ‘Tiny Violin’ on a daily basis,” Gorby says. “Within the first few days I came across a random Twitter post: ‘Tiny Violin is the one iPhone app every true asshole should download.’ Then there were a few blog posts saying the application was indispensable, as well as a few calling Tiny Violin worthless, and even accusing me of being a scam artist! This was success for Tiny Violin—people actually finding this little application remarkable enough to talk about.”

Gorby says he continues to be surprised by the “passion and expectations” people have for iPhone applications. “Apple has set the bar pretty high with the standard set for iPhone applications in both aesthetics and usability,” he says. “Developers not meeting these standards will find their applications with a one-star rating and a home in some blog’s ‘Worst iPhone Apps Ever’ post—Tiny Violin has gotten a couple of the latter.”

Gorby is a full-time developer for a digital agency by day and an iPhone developer by night. About 12,000 copies of Tiny Violin have sold on the App Store so far, and, of course, Gorby has to surrender 30 percent of his proceeds to Apple, per the iPhone developer agreement.

Brian Gorby has netted almost 10 grand on a 99-cent iPhone app called Tiny Violin.

His advice for would-be developers is to go for it. “Put something together and get it out there. Expect a few failures here and there, and you’ll never be disappointed. There may be no original ideas left, but there are infinite ways to execute on any idea…with the possible exception of those tip-calculator apps.”

Henk van Ess, 3G Juice (3gjuice.com) 

“Embrace your irritation,” Van Ess urges aspiring entrepreneurs. In his case, the thing that aggravated him the most was his iPhone 3G’s battery life. A Web 2.0 consultant, speaker, and investigative journalist, Van Ess’s iPhone 3G quit for the day long before he did.

So he posted a note on professional networking site LinkedIn asking people to point him to the smallest possible rechargeable add-on battery for the iPhone. A rep from China BAK Battery contacted him with info on the company’s product, and Van Ess liked the battery so much he began selling it himself, first ordering in bulk to save friends the cost of shipping and, eventually—as word spread through assorted social networks and friendly strangers began asking where they could buy the wonder battery—opening an online store. Van Ess then went on to develop a new version of the battery, the 3G Juice, which he says improves on the original.

Van Ess believes passionately in total transparency. He reveals all on his blog at 3gjuice.com, listing the names of suppliers and even detailing production failure. Being open about what he knows and doesn’t know has resulted in “a lot of great free advice from smart people” who want long-life batteries for their own iPhones.

Henk Van Ess needed a better add-on battery for his iPhone 3G. When he found one, a side business was born.

Although 3G Juice is a side gig for Van Ess, it’s a growing worldwide venture. He swears success will not change how he runs his business. “My customers are intelligent people who have good radar for marketing blah-blah. Even so, if you are honest, you will lose some customers who want to be seduced by you (buy this and you will be happy!). It’s really all about authenticity and sharing ideas.”