Why can't I delete movies from my iPhone 4, either from the phone or through iTunes? I was on vacation and took some videos, and now the iPhone 4 memory is near full.  So I tried to delete other experimental movies I made using Handbrake, so that I can take more video or photos, but if I plug the iPhone 4 into my Notebook computer, I can seem to delete it on iTunes?

Maybe because the computer I sync with the iPhone 4 is at home (a desktop), but not with me on vacation.

I can't delete it on iTunes, can't delete it on iPhone itself.  I am stuck during the vacation, or is there a way to handle it?
While not a SuperUser-compatible answer, since the computer interface is missing, I just did the following:


Open the iPod app
Go to Videos 
Swipe over a video from right to left
Press Delete
Confirm
Done!


No computer needed. Also works for music