Go to
www.GuildWars.com, they have a key for everyone in America, and a separate key for Europe. You can only create Player vs Player characters in the current offer they are running, but at least it you can sort of get a taste for what the game is like. If you are thinking about getting into the MMORPG land, I would say that Guild Wars is a good place to start, no additional costs, strings attached, etc. There are some other cool nuances to the game, and if you're interested PM me, I've been playing the game on and off for about 7 months. But here's the two keys for now (you can download the game from their website, and when you install the game enter the key at that time...)
America: 888D9-H27PG-NM72D-PLHJ1-2HG11
Europe: 66DG9-C4RHB-9FKD6-287BJ-LRGCJ
Oh, and they'll ask for an e-mail address, but this is a way to provide some control for them from people trying to exploit the game. Don't worry about spam, haven't gotten a single thing from them.