in fact, I think that the BEST way to join TA is the EASIEST.
join a miniteam. Russ's TA-Cube, and the TA-Federation are just two of our miniteams. if you ask in the distributed.net forums, you can join in just 5 steps (or less!).
in fact, I'm seriously considering joining a mini team, becuase I personally want to see more competition within the team (allowing for more people wanting more speed AFTER we become 1st overall).