Currently I am installing iPhone firmware 2.0, I downloaded it from here, remember that according to the knowledge base article it will erase all of your iPhones data, so sync your iPhone before updating. To install all you do is option+click on “check for updates” and then choose the ipsw file. Be sure you have iTunes 7.7.
It takes quite a while, I’ve been updating for 10 minutes already and it still isn’t done so, be patient. I’ve already downloaded a couple of applications from the App Store so I’ll be spending quite a bit of time playing with the apps that look interesting and possibly doing some reviews over the weekend.
Update: I just restored the settings to my iPhone and everything seems to be working just fine. I have the App Store and a Contacts application on my homescreen now. It looks great.