You will need some way of inporting the video - either a video-input on a graphics card or a dedicated capture card. I use a LEADTEK WIN2000XP, but there are plenty of other options - Pinnacle make some good ones.
You then need to convert the captured video (usually an AVI file) to MPEG and then to a DVD - I use TMPGENC to convert the AVI files and NERO to burn the DVDs.
+R and -R are simply 2 different types of recordable DVD - a bit like VHS and Betamax when video recorders first came out. Most DVD players will play back both types (check the manual first though), but most DVD Writers only support one format (Sony, NEC and a few others make writers that will use both - but they are more expensive)
The best place for advice, tutorials, reviews of capture cards and DVD writers and some excellent forums is: