With the advent of "legalized" jailbreaking, a few sites are popping up to take advantage of the situation. One that's hot right now with a lot of owners is JailbreakMe, a site that helps you with step by step instructions after you open up the site on your iPhone 4. No software to install is promised, but the site's been pretty busy so have a little patience with load times.
Facetime fans who give jailbreaking a go can also use a program that will allow Facetime chat over 3G and bypass the current WiFi only restriction. My3G promises to allow 3G Facetime chatting after install, and has a free trial you can use before shelling out the 4 bucks they ask for the full version. Sounds like a nice way to give your new expanded access a try, right?