The HD episodes aren't on Netflix streaming yet, but they are on Amazon Prime. As for the physical discs, I don't have the Netflix disc-by-mail plan anymore, so I can't tell you if they have them or not.
But I do know that if you live in the U.S. you can rent them from 3D Blu-ray Rental dot com (just search Google). I've never used the service, so I can't vouch for them, but it looks like they have all the CBS Star Trek TV Blu-ray releases and according to their site you can rent each disc for $3.99 and keep them for 7 days, or you can choose an unlimited monthly subscription plan.
So there you go.