VNC (virtual network computing) has been around for a long time, but lately there seems to be more and more interest in it, perhaps because of all the iPad and iPhone owners who want to connect to their computers back home or at the office.
Screens, from Edovia, is a new entrant in the VNC app race. It is on sale at US$14.99 for a limited time, after which the price will go up to $24.99. The app is universal, so your purchase allows you to install it on both an iPad and iPhone, or an iPod touch.
Like many other similar apps, Screens has support for many multi-touch gestures, as well as squeeze motions to enlarge or shrink the screen back down. The main difference is that with the other apps, you use those gestures to move a cursor around the screen or, in some cases, move the screen around a stationary cursor. Screens allows you to control the remote computer using your finger as a virtual mouse or trackpad.
Of course, you have to run a VNC server app on the machine you want to connect to, and you can find those for Windows and Linux. OS X has VNC built in; you just activate screen sharing in the Mac Sharing preference pane. If you have multiple PCs set up to connect to, you flick between those screens on your iPad, iPod touch or iPhone.
I've tried it at home, and I was easily able to connect to my desktop Mac and a Windows XP PC. Using the app was a pleasure, and because of the way touch is integrated, it felt like a pure multi-touch app rather than a screen emulator. There is a dedicated keyboard, and a second one with keys that relate to the type of computer you are connecting to. For example, you can invoke a Spotlight search with a tap when connected to a Mac.