More than like the above is correct but I doubt it'll be early 2013. Currently, they are working on a server merge which will consolidate their 2 servers into one. Next on their list is to finish up the engine and you will likely see a full profession rebalance by the end of next year.
AO is still my favorite MMO. I usually pick it backup every little bit but it's getting harder and harder since so few people play. The server merge should help that quite a bit. The new engine and profession rebalance should bring new and old players back into the game.
The original game is free to play. All the expansions and extras that go with it aren't. The game you played back then would be whats free to play now. Ideally, if you start playing again it's best to try and join a friendly org(clan). They can help you out with questions, running through content and giving you free stuff.
A lot of players have alternate free to play accounts that they level toons for buffing or to run specific dungeons. After the server merge which will hopefully happen in the next few months, there should be a lot more people around to play with.