And One More Problem...

"While Apple's iPhone 4 signal loss issues have been receiving significant attention since the device's launch late last month, a number of other problems have been seeing sporadic reports, and one of the most prevalent of late has been problems with the device's proximity sensors designed to sense when the phone is held up to the user's face and deactivate the device's screen, thus preventing unintended activation of buttons on the display."

According to some reports if you do the following it provides a fix:

...open the Settings app, then go to General -> Reset, and choose "All Settings" at the top (note: this will not erase your apps, media, or other data -- that's what the "Erase All Content and Settings" button just below this option is for. "Reset All Settings" just reverts any Settings preferences you've customized back to their factory defaults). One Twitter follower, Brian Partridge, reported that AppleCare told him to just use Reset -> Reset Network Settings, not all settings, and it worked.

The iPhone Blog also has some tips regarding this issue [link]. I'm feeling lucky that all I've had to deal with is a battery issue, that was fixed pretty easily by draining it and recharging. How about you, have you experienced any of the problems we've posted on with your iPhone 4 or with iOS 4?