Yesterday when we posted that iMovie for iPhone 4 was available on the App Store, we mentioned an important limitation on the resolution of the videos you can share with the iPhone. An Apple support document specifies that while iMovie can export a full 720p HD video if you
Since then, users like Chris Pirillo have started using the app and have confirmed the restriction. Chris asked us if there are any iPhone-only workarounds that don't require transferring the video off to your Mac or PC. Unfortunately, it looks like the only way you will be able to share a full 720p HD version of iMovie videos is to transfer the file to your computer before uploading it to YouTube or any other sharing service from there.
Ironically, while a second support document mentions this limitation is in place to improve upload performance, you are still restricted to 568x320 even when you're connected to WiFi -- perhaps the very same WiFi connection you will now use to upload the video from your computer.
Chris also mentioned he and other users are reporting issues logging into YouTube with both YouTube and Google credentials on a number of iOS devices. We're not sure why this issue is happening, but a few people on the Mac Rumors forums are suggesting that you make sure your Google credentials are associated with your YouTube login. You may also want to verify that your email address is confirmed in the email options to possibly eliminate the problem.