I'm a bit confused as you mention DV tapes and DVDs. Are you planning to incorporate footage from the DVDs with DV footage from a camcorder?
If this is the case, and assuming the material is copyright free, I would rip the and convert the parts of the DVD you need "on the fly". Assuming you there a relatively small amount of material from the DVD, you can convert this to DV and include within your Premiere Project. For a guide to conversion, see Part 9 of the FAQ:
http://www.videoforums.co.uk/reviews/faq
To author the DVD you will then need a seperate authoring application as Premiere 6 does not have this facility.