Apple’s Mac App Store may not be the runaway hit that the company has had with its iOS sibling, but developers are slowing coming around to the new way of doing business. Case in point: The popular application 1Password has finally arrived on the Mac App Store in an OS X Lion-only edition.

Agile Web Solutions has announced the availability of 1Password 3.9 into the Mac App Store. If you’re not familiar with 1Password, it’s an online password and identity companion that goes far beyond simple password storage, complete with an iOS equivalent and Dropbox sync for keeping your login information, credit card data and much more secure and handy at all times.

1Password 3.9 signals a new direction for the app, which has been built specifically for OS X Lion and 64-bit. Users will now have access to full-screen mode and even better security thanks to the app being sandboxed (a Mac App Store requirement) as well as PBKDF2 Calibration. 1Password 4 is also on the way, which will be a Mac App Store exclusive -- no more buying directly from the developers’ website.

Because of the shift to the Mac App Store, Agile is offering 1Password 3.9 for only $19.99 for a limited time -- that’s a full 50 percent off the regular price, and will allow existing users of the app to not only get on board the Mac App Store train, but also get a free upgrade to 1Password 4 when it’s available (the same also applies for new users, of course).

Speaking of existing users, Agile has posted an extensive Q&A on their website which details the simple process of moving to the Mac App Store version, and lists the changes made to the app for longtime customers.

1Password 3.9 is available now for only $19.99 from the Mac App Store; the 9MB download requires Mac OS X 10.7 or later and a 64-bit processor, but hurry -- the 50 percent off price is only valid for a limited time.

Follow this article’s author, J.R. Bookwalter on Twitter