If, like me, you treacherously updated your iPhone to 3.0, in order to get the latest and greatest software or just to experience Copy and Paste in all its glory, then you spent the time going through the backup process, which seemed like an eternity and the reboot process.
The next morning you awoke and forgot to download that all important app or you found out it wasn't in your homepage. Or you just remembered that you had to recreate the scene from Office Space where you pretend to be a rapper, even though you're really a suit and tie guy/gal. You try to hook up with iTunes and suddenly your iPhone is no longer recognized.
What do you do? Well first of all, like a good geek, I went to the Apple forums, where you can get an answer to almost any question in regards to your software/hardware problems within minutes. It's sponsored by Apple, but mainly answered by die-hard fanatics and it is a diamond in the rough when it comes to information. Today, that failed me dismally. The information that I got did not work.
Then I called my closest Apple store. They suggested redownloading iTunes and/or reinstalling iPhone 3.0. The latter by the way paved the way to another question, which was answered badly: Can I downgrade to iPhone 2.2? NO! Was the answer, you can't. Now you know.
I didn't do any of the above. After 2 hours of tinkering, including turning on the computer, turning it off; turning on the iPhone, rebooting the iPhone, Soft reboot, Hard reboot, I finally tried something that I had learned in the Windows World 3 years ago, just before I did "an office space massacre" with my shoes (remember the scene with the copy machine?). That event led to my first iMac.
Anyway, without further procrastination, here is what I did and it worked flawlessly:
1. Turn off the iPhone and disconnect it from the USB connector.
2. Hard reset the iPhone.
3. Turn off the Computer.
4. PLUG OUT THE COMPUTER
5. TURN ON THE COMPUTER (WITH IT PLUGGED OUT -- YES, WITH IT PLUGGED OUT, TRUST ME)
6. Leave everything off for 30 seconds to 1 minute.
7. Plug the computer back in and restart.
8. Boot up iTunes (and iPhoto if you've got it set up that way).
9. Plug in the USB connector. iTunes should recognize the iPhone now.
Let me know if this works for you. It worked well for me and increased productivity too. I was able to get back to work (it was a day off) on important things and enjoy that fruity iPhone goodness.