Nice find, just use/create an NCSoft account (free) and download the client. If you already have one, such as Aion, Guild Wars, or City of Heroes, you can use the same account.
Pretty excited to try this, I love NCSoft and I've been in a mech mood ever since they announced MW4 for free and I found Virtual On on the PS2.
I could swear I made an account for Guild Wars. I don't know what the password is, gotta find it out. Seems like this is free-to-play with microtransactions, so I don't have to worry about the price changing?
Aww, and they won't pay for my internet bills.
Edit: uh, Seven compatible I hope? Only lists to XP.