Re-install itunes8.1 did it
had the same problem with my PC today. Won't recognize and not show any charging (but still charge... meminfo showed the battery level increase). On my MAC everything worked fine (same cable).
So I just upgraded itunes from 8.0 to 8.1 and already DURING installation (probably when unloading/loading the iPod Helper services or something) it recognized and the "plugin sound" came and charging status on the phone.
This won't be a solution for any hw problems, but maybe to some of the others....
Solution - Change IC LT 4066
This is caused by a hardware fault on IC LT 4066 the power and usb IC it need to be changed .Anyone else correct me if im wrong
Iphone not recognized by Windows, home button not working
If you have recently dropped the iphone your problem may be in the #4 ribbon cable. (i had not droppe mine..but..)
Not recognized by windows
Not charging (apparently)
phone calls people could not hear me (speaker or normal)
home button not working
1st thing is that the phone will charge if you leave it in. you just wont see it charging and then all of a sudden it will go to a full charge.
Open phone ( hopefully you know how, if not 2 screws.., suction cup.., pull and open carefully!!!)
remove the 3 front panel cables. (if you have not done this LOOK IT UP, you can break the cables if you do it wrong) the #4 ribbion cable is the one that connects the bottom assembly with the main logic board. remove it and then reseat it.
put phone back together. hopefully you will be all good
put phone together