This may seem like common sense to some but there's an easy way to tighten up a loose USB port on your droid. My first droids port became loose about 2 or 3 months ago and it was extremely annoying in the car dock, I just got a replacement one and it's port was loose to, so I decided to try something.
All you have to do is bend the USB housing inward a little where it splits (on the bottom side) with a thin flat object, such as a razor blade. Use a twisting motion instead of a prying motion and your droid's USB port will be as tight as size 0 jeans on a fat girl!
Do this at your own risk!!!