There are three parts to this.
1. Movies should appear on the "Video" portion of the PSP's menu. If they are not:
2. The movies were not properly transferred. It's important to note that PSPs will only play MP4 format video files. If the movie you moved to the PSP is not an MP4 file, it will never appear on the PSP video menu.
I have transferred a few movies to PSP, but I never ripped them myself. I have the following software package from ImToo. It rips the movie, converts it to MP4, names it properly, and transfers it to the PSP for me:http://www.imtoo.com/dvd-to-psp-suite.html
3. If you have already ripped the movie as MP4 and it's not showing up in the video section, here's what you have to do:
Connect your PSP with PC, and copy those two files into
"H:\MP_ROOT\100MNV01" (where "H" is the drive letter of your PSP).
Re-name your files in PSP. You must re-name them to "M4Vxxxxx.MP4".
There would be five random numbers followed "M4V" and the two letters
should be capital. The numbers must be same for two files. This is
quite important, or your file can not be played on PSP.