i bought the mini-dvi to composite (video) adapter from jr.com to project from my 12" PB to my 27" FlatScreen TV, but the resolution isn't all that great... i'd just buy a projector and set it up via VGA
I just plug my pb into my tv with the DVI cable. If I'm ever at a different tv without DVI I just use the svideo, and if not I use the svideo to composite adapter than came with the powerbook.
the only problem with this is that all the sound is going to be played through your powerbook, so either have a way to hook that up to the tv, or your movie may be a bit on the quiet side