Premiere 6.5 was the last of the line. After that it went to Premiere Pro. From there to 1.5, and now we are on CS6, soon to be either CS6.5 or CS7 (they haven't officially said but I think it is CS7).
Learning CS6 would be to your advantage. It takes a little while to get used to single track editing instead of the way 6.5 works. Transitions will confuse you for about 5 minutes, but that's it. Everything else is better. MUCH better.
There are literally hundreds of free videos on creativecow.net to help you get started. Also, if you sign up for the Adobe Creative Cloud, you can pay by the month instead of putting all of the money out front - and you will always be on the latest and greatest software. All of it. Not just Premiere Pro, but After Effects, Photoshop, Dreamweaver (or Muse), etc.