Fileplanet has keys available for the AoC 'Open Beta'. Not really sure how open it is when you have to pay for a fileplanet subscription to get hold of them! Actually, the beta keys are available elsewhere, but it seems most sites are having various contests whereas Fileplanet is using a first come first served method.
I bit the bullet and shelled out the $16 for a quarterly Fileplanet subscription. I hope to get some use out of my money by downloading demos for games I've heard about before I cancel it. I discovered after I had already signed up, that if you hit the 'No Thanks' option in the bottom right of the subscription chooser page, apparently you're then given the option for cheaper subscriptions!
I downloaded the entire 12 gig (!) client last night and found out this morning it was corrupted! So, I went ahead and installed Fileplanet's download manager which looks like it will be a much safer bet for acquiring the client without problems.
Anyway, hopefully I'll be able to check out AoC for myself soon and get an idea of how this game will play (unfortunately, there will be a level cap of 13 for this beta, which seems kind of lame. And, now that I think about it, might be an inadvertent message about the state of their game at later levels). Expect to see a couple of first impression posts from me once the beta opens (which is May 1st I believe).