Since I'm in the process of writing my part of a grant proposal before heading off on a trip, I figured, "Hey, why don't I update my iPhone to the 2.0 software?" The software is unofficially available; see this iLounge article for a good summary of how to get it. Here's how things went:
11:55AM: Option-clicked "Check for Update", selected .ipsw file, iTunes extracted update.
11:56AM: iTunes started "Preparing iPhone for software update..."
12:02PM: iTunes started "Updating iPhone software..."
12:04PM: iTunes started "Verifying updated software..."
12:06PM: iTunes started "Updating iPhone firmware..."
12:09PM: iPhone restarting, iTunes sees it, offers to set it up anew or restore from backup. I restored from backup.
12:11PM: iPhone restarting
12:12PM: iPhone reappears in iTunes list. Arrangement of icons same as it was before update. Only immediately apparent differences are "Contacts" and "App Store" icons. Set up synchronization in iTunes to sync all applications. Synced iPhone. 12:30PM: All done, now to see if it works...