The iPhone 3G officially launches in the US tomorrow, but if you need your iphone app fix early it is now possible to download the newest version of itunes (7.7) and access a library of apps ranging from $0 - $10; an official AIM client, social media add-ons (myspace, twitter, facebook etc), games like Super Monkey ball and a whole lot more.  There is a caveat though; old iPhone users will have to upgrade their firmware early using the method posted on MacRumors.