We've been through this before -- there are no (100%) legal free applications that will decode CSS-encrypted DVDs (ie, most commercial ones).  There are programs out there that will do it, but their legality has not been decided by the courts.  The DVD Consortium's position is that the DVD format is proprietary, and they should get a commission on every software and hardware DVD decoder.  As annoying and obtrusive as this may sound, it has legal precedent, and so free DVD decryption software is probably never going to be 'legal' (not that they can ever stop it at this point).
Personally, I think it should be legal to decrypt DVDs that you own, in order to make backups so your kids don't destroy the originals, put them on your laptop so you don't have to take the physical DVD with you, etc.  I'd love for it to be a free standard, but that's just not going to happen while Hollywood's involved.