Yep, I think it's an A. americana 'Marginata'. I've had one in a pot for about 3 years now, and while it has grown fairly fast, the pot seems to keep it somewhat under control growth-wise.

cd

Way too small to tell - where did you get it?
Peyton

I got it from a BCSS member, could it be a form of potatorum(sp)?

Larry,

Hard to say, it needs to grow a bit.
If I had to speculate, I would say it resembles Agave parryi patonii marginata, AKA Agave 'Merico'.

Peyton