I know Mustangs Unlimited sells a pretty decent video and theres also a site that has tear downs and rebuilds in PDF format but Im at work so I dont have the link. Im sure someone else will, just keep bumping this thread.
A T5 rebuild kit with syncros, bearings and other small parts costs about $160. It does not include any gears or shafts.
http://cartapes.com also has a video on how to rebuild your T5 or Tremec. It costs less than $20, and is worth every penny of it.
I did a Tremec 3550 rebuild, and it wasn't that difficult. The video was an immense help, and I would recommend viewing it. At $20, it will give you an opportunity to look and decide for yourself if you think that it is something you want to try to do.