Cannot figure out what to do.. Interested in this girl..

I am interested in this girl for a while now but nothing has really happened, except a couple times we walked past each other and smiled or said hi. One of my friends keep telling me to add her to facebook but that would be creepy. Btw i got her name from one of her friends, a guy. Anyway i found out recently she is on Twitter, and i was thinking i could follow her to see what happens, but still i think that would be weird. I can't think of how i could introduce myself in person... Help? Thanks!

Grow some balls and introduce yourself. Stalking her on twitter is being insecure and creepy. Girls like a guy that is confident enough to come right up and talk to her. There is no other way around this.

"Hi, I've seen you around (insert place here) a few times. My name is (insert name here), what is yours?" Go from there.

A lot less creepy than stalking in the shadows on Twitter or Facebook. You don't get a girl by liking her pictures, you get a girl by actually communicating with her.

Just walk up to her, do what Red Apollo said and everything will flowi great, and you're suddenly in a conversation with a girl you were previously stalking on Twitter.
And talking from personal experiences, you probably won't have to think about adding them on Facebook for future conversations; they will probably add you. Good luck!

This is always an issue with insecure guys. They look for alternatives to avoid actually having some come courage to talk to the girl.