I'm planning on shooting 24p and 16:9 for my upcoming short film. When editing in Final Cut Pro, do I have to adjust any settings so I can edit in 24p, or can I just capture and edit in the timeline? I'm asking because I've been reading posts about people running into problems with this. Thanks.

Just capture and edit on a 24p timeline. The program will adjust to 23.976 timing automatically.

Lock the camera to a 1/48 shutter speed.. or you'll not really get the benefits of shooting 24fps. :)