LogMeIn’s ignition client isn’t the cheapest way to remotely control your PC or Mac from a smartphone or tablet, but it’s quite slick and easy to install, and currently going cheap.
LogMeIn’s remote access on the PC/Mac is phenomenal, because it’s both free and allows you to control one machine from another machine as easily as anything else we’ve seen. The iPhone/iPad app has also been good, but not quite as good, until now. (It’s super-improved, is what I’m saying.)