I'm going out on a limb here but i think that's what Facebook is all about?

as waiting4 said, i wouldn't poke. i always associated poking with a deep friendship that may lead to some sexual tendencies. who knows, maybe I'm totally off base.

if you guys went to the same college then I'm sure she would notice this if you sent her a friend request and it wouldn't be a total creep scenario. but you did say she has noticed you so she would likely accept the request without hesitation or doing in investigating.

shoot her a friend request and wait a few days after she accepts it to see if she initiates contact, if not, then I would send her a friendly message. I think it would be flattering for a female to know that you always wanted to say 'hello' to her but were never put in a good scenario where this was possible, and you were to nervous to talk with her while she was with her friends.

but you definitely need to talk to her. because if you don't.. you'll regret it for a long time to come.

good luck my friend!