Here's something I wrote a week or two ago in response to another question, about when to deinterlace and when not to:
Advice on Video Editinig issue please!
As for selecting frame-rates, normally you would choose the framerate that matches your source footage, unless the way your video is going to be viewed dictates otherwise. For example, if it's going to end up on Vimeo or YouTube, go for 24 or 30 frames-per-second (as Flash video is converted to 15fps, and these numbers seem to work well).
Andrew.