Right now, I'm across town using my home computer from my iPhone. The LogMeIn app ROCKS!!!
There is a bit of a learning curve, but worth $29.99, if you need access to your home computer from the nether-world.
I will post details once I'm better skilled.
**UPDATE** March 19, 2009
I'm still learning. This is great on the iPhone - but it will be SPECTACULAR on the iPad!!!
Here are a couple YouTube videos by aramistech.com that will explain it for the iPhone in detail.