First off, you'll want to maximise the quality of the footage, so when you RIP from the DVD, rip to DV. This will minimise any degredation in quality as it's not very compressed (and hence creates HUGE files). Riping to DV will also ensure you'll be able to edit properly in Premiere (editing with compressed footage is a nightmare).
If you don't have a DV codec, you can download the Panasonic one here:
http://users.tpg.com.au/mtam/install_panvfwdv.htm (I think this is an encoder too, I know some DV codecs are decoders only (which strictly speaking means they're not codec
))