An iPhone has been detected, but it could not be identified properly.

Try this support doc method to restore the iphone. It worked for me.

http://support.apple.com/kb/HT1808

Had the issue on my work PC that had VPN software and since I couldn't disable it I used my home computer and the problem went away.

This was something that was happening to me with the release of iTunes 8.2, I was intermittently getting this message or an error code 0xE8000065. What I've eventually had to do is stop trying to get it towork with the PC and I just installed iTunes on the laptop instead. I think we will see an update of iTunes released very soon.

I have been having the same problem. By disabling the wireless and then connecting the iPhone, I have very good result. I think some of the inconsistency that I had seen earlier is because I typically use a cable connection at work and wireless at home. With a cable connection to the internect, the iPhone was recognized even though the wireless was on (but I am not sure if that is always the case).

None of these suggestions worked for me. Then I tried switching USB ports (with WIFI off and network cable unplugged) and itunes recognized my phone right away.

I get the following message whenever I connect my iPhone (3G, 3GS & 2G) "An iPhone has been detected, but it could not be identified properly. Please disconnect and reconnect the iPhone, then try again."
I have uninstalled iTunes 8.2 using Add/Remove Programs and deleted every apple file I could find before reinstalling. I have hot-rebooted my iPhone in the cradle with iTunes open.
I then reset my iPhone from the Settings screen and this turned it into a brick because it was wiped but iTunes still couldn't connect to it to activate it. The next morning, as soon as I put it in the cradle at work (Dell XPS WinXP sp2) it was recognized and activated (but without any of my settings, apps, photos, ringtones, etc.). I copied the iTunes backup file from my home computer to the same directory on my laptop at work and restored from that backup. I upgraded my 3G to 3.0 at work on the 17th but iTunes still would not "properly identify" it at home on my Vista machine.
I bought my new 3GS on Friday and restored it to my backup at work (XP SP2) but no luck at home using Vista SP2 64 bit.
My Genius Bar appointment was similarly fruitless on Saturday at the Apple 5th Ave. store. I have tried everything I've seen on these discussions, including: installing using compatibility mode; shutting off wi-fi (which I don't have)updating USB 2.0 drivers (I tried every one of the 6 ports I have, powered and not).
I will try your added suggestion of disconnecting from the LAN and throw in a shutting off Blue tooth (must find a keybourd though).
Let me try

Okay, I'm throwing in the towel for now. I unplugged every USB device, turned off my Bluetooth keyboard and mouse, unplugged the wireless router and unplugged the cable, turned off wifi on the iPhone, and using a USB mouse I started iTunes. By the way, it seem to take an awful long time just to start up besides not seeing the iPhones.
Then I plugged in my iPhone and waited. Nothing at all. No error messages but no iPhone. I turned it off and on, left it hooked up while I restarted iTunes, did a hard reboot while it was plugged in. NO reaction whatsoever from iTunes.
Then I happened to notice that Skype was doing something in the system tray so I (for the heck of it) disabled it and immediately got the old error message that an iPhone has been detected but can't be identified.
This eco system is too fragile. Even if I got my iPhone identified once I could never be sure that I wouldn't breathe the wrong way and knock it out again. I'm going to live with my bizarro work-around of connecting to a spare XP tower (no keyboard, mouse or monitor) that can sit on my network at home and control the iTunes sync via GoToMyPC. This was the PC I was using before the Vista machine. I guess I'm using it as a iTunes 8.2 server.
This has to be an issue that Apple addresses in the not too distant future, one would hope. I'm going to try and wait it out.

UPDATE I just got a call from an Apple representitive responding to my survey response after my visit to the Genius Bar. After explaining that since I have found a work-around I can live with I won't be trying anything new until a new version of iTunes comes out I informed him of how wide spread the problem is judging from the Discussion Boards and how frustrated we all are. He asked me to forward the thread to him and he would escalate it to the Engineers and keep me posted. Cross your fingers everyone (but don't hold your breath)!

I was forwarded a Tech Article by Apple(it appears to be an older rather than newer article) about steps to take if iTunes doesn't see your device. I was asked to make sure I have tried everything in it and then reply, which I am doing now. The article is at

http://support.apple.com/kb/TS1495?viewlocale=en_US

incase you want to look at it. Good luck!

I have been sharing this same frustration for the last few weeks; iTunes cannot identify my phone. In my case this only happens when I am connected to the internet at home (wireless). When I am in the office my phone syncs like a champ; I have done this now at my offices in 2 different cities with no problem at all; I am not wireless at the office and don't know if that contributes to the problem or not but its the same laptop, same phone, same cable and there is no issue. Interested in any similar experiences.

Your experience sounds as if it would be very helpful to the diagnosticians at Apple since it is virtually the same machine in 3 different places. Your laptop is like a control and your network is the variable that causes or solves the problem. Am I correct in that interpretation?

You are correct, the only variable is the network connection. How do I contact some one at Apple to share this? Do they read these posts by any chance?

Just downloaded itunes 8.2.1.6 which was suppose to fix the syncing issue. It did not. I still have to turn off my wireless and disconnect from the lan. Totally disappointed. Love my 3GS but hate having to dance around to sync.