I'm shooting a short for viewing primarily on YouTube and short film festivals. I want it to have a 'film look', as they say, so which frame rate would be the best to shoot in in terms of quality and convenience for distribution?

If I were you I would use a camera that can shoot in 24p. Or if that's not possible, shot 30p. I did that on my short film and put it on youtube and it looks fine; you will always lose quality when going to something like youtube because of the compression, but youtube as far as i'm concerned can handle 24p stuff.

Also remember; good lighting, composition, camera movement, and acting will also sell the "cinematic look."

well as far as i know frame rate is important in televison where NTSC and PAL issue arises...but in films the universal framte rate is 24 frames per second...

i dont know is it true or not but a multimedia teacher told me this....

If you want it to look like film, shoot on film, maybe super-8. Just a frame rate setting won't do it. Are you going for a certain film look? Scratchy, 70s, studio flicks...