iOS devices are great on their own, but if you're constantly using your Mac for work or other personal projects, you might feel like you're not fully utilizing your iPad and iPhone. With a few applications, however, you can transform your iPhone into a trackpad or your iPad into an external display and control desktop applications like Keynote and iTunes right from your mobile device. Read on to find out how.

How To Use Your iPad as an External Monitor

With an application called Air Display, you are no longer limited to your MacBook’s screen size while traveling or working. As long as you have an iPad, iPod touch, or iPhone, you can extend your Mac’s screen to these devices, giving you extra room to move windows around. Best of all, you can actually touch these windows on your iOS devices instead of having to use your mouse.

To get started with Air Display, download the $9.99 Air Display application from the iTunes App Store. While that’s downloading, head over to the Avatron website and download the free software for your specific Mac or Windows machine.

After both applications are installed, open Air Display on your iOS device. Next, navigate to System Preferences > Air Display on your Mac. Flip the OFF switch to ON, and then select your iOS device from the “Devices” drop down menu. When you do, your Mac will extend the display to your iOS-powered device.

How To Use Your iPad or iPhone as a Multi-Touch Trackpad

Mac trackpads are great, but if you don’t have a portable Mac or $69 Magic Trackpad, you can’t join in on the Multi-Touch fun. Luckily, though, if you have $4.99 in your iTunes account, you can purchase Touchpad from the iTunes App Store. This application turns your iPhone, iPod touch, or iPad into a Multi-Touch trackpad, wireless keyboard, or iTunes remote.

After downloading the application from the iTunes App Store, navigate to System Preferences > Sharing on your Mac, and check the Screen Sharing checkbox. After doing that, click Screen Sharing > Computer Settings. Check the box labeled “VNC viewers may control the screen with password” and specify a simple password that you will enter in the iOS application. When you’re finished, click the OK button.

After doing that, open the TouchPad application on your iOS device and tap on the small gear in the top, right-hand corner of the application. Tap on the blue arrow next to the Mac you wish to connect to, and specify the VNC password that you typed into the Screen Sharing section of System Preferences. When you’re done, click Save. To connect to your Mac, tap it in the Servers list.

You should note that there are plenty of applications that provide this same functionality. Feel free to shop around to find an iOS Multi-Touch trackpad application that best suits your needs.

How To Control Photoshop, Keynote and More

There are many other ways to integrate iOS applications into your Mac user experience. Here are a few more applications:

- Keynote Remote ($0.99; iPhone or iPod touch)
- Adobe applications for Photoshop (Prices vary; iPad)
- Rowmote Pro ($4.99; iPhone, iPod touch, or iPad)

Do you have another application you use to control or interface with your Mac? Let us and other readers know in the comments below.

Follow this article’s author, Cory Bohon on Twitter.