Sorry, I'm thinking Pal...since thats where I live.
And NTSC is actually 29.97 Fps...somehow
With the OLED screen the device uses, videos won't really be that good anyway, but to answer the question:
Storage capacities: 1GB, 2GB, 4GB, 8GB
Supported audio: MP3, WMA, WMA-DRM, Audible, WAV
Supported video: Motion JPEG (15 fps)
Extras: FM tuner, photo viewer, voice recorder, line-in recording, organizer, removable disk
Dimensions: 2.7" x 1.7" x 0.6"
Weight: 1.6 ounces"
So it looks like from the specs, since it only uses a OLED screen, its capped at 15fps, running off a JPG animation to keep sizes down with videos.
Its an MP3 player at heart anyway. Its not truely meant for videos.
If thats what you wanted, a Zen Vision M (320x240 screen) or a Zen Vision W (640x480 screen) would have been better for you.