I just found out (via @chriscoyier) about a way cool iPhone app: Mobile Mouse, only $1.99. It turns your iPhone (or iPad or iPod) into a remote mouse, trackpad, keyboard, etc. for your PC or Mac — or for multiple PCs and Macs!
The overview video had me sold about me halfway through (it’s a long video, about 9 minutes), and it was a matter of minutes to download the app, download the corresponding software for my Mac and PC, start up the software to turn the computer into a server (I didn’t have to adjust any settings), start up the app, and let it automatically connect. It’s super-easy to switch between controlling the Mac or PC by hitting the ‘settings’ icon in the top left corner of the phone screen and choosing which server to connect to.
I had some trouble getting the “air mouse” feature to work until I looked at their support page and figured out that instead of trying to move the mouse like a laser pointer, I had to tilt it from side to side (true for iPhones 3GS and below). You can easily switch from “air mouse” to “trackpad” — and the trackpad works horizontally or vertically. The keyboard can be shown or hidden and there are easy buttons to switch to view all your programs/applications, a browser-specific button panel, or a media button panel. The media button panel is smart enough to know if you’re using iTunes or DVD or Windows Media Player or whatever. It’s going to be perfect the next time that Steve and I watch DVDs on the laptop.
I am not so sure how much I will use this app, apart from DVD-watching, but overall I’m quite impressed with its functionality!