CD based: CloneDVD, CDRWIN, Nero

DVD based: DVDDecryptor (ISO Mode), Prassi Primo/Record Now, Alcohol120%

These seem to be the most widely used right now. Prassi Primo (the original version, before it went retail as Record Now) can still be nabbed for free. It's posted on a few Warez sights, so it won't be posted here, but if you search for it properly, you'll find it. You just need to get an updated PxEngine from the Sonic or Stomp sites (RecordNow Support downloads).

Raist