Facebook is the creepiest thing ever.
I met most of my friends through online games.
Third of them creeped me out, other third were pervs and (some old) dudes pretending to be girls,
the rest of the 'normal' people had their issues with time
so I narrowed it to couple of them, added them to msn
then third got blocked (mutual) due to I don't remember what
third turned out to be mental, deranged and sociopaths
and so I had around 7 people left.
and today I talk with only one girl.
The point is, I am currently with one of the dudes who pretended to be a girl (and whom I eliminated among the first). And we are doing great! Lovey dovey
So! It is always going to either sound or be creepy over the internet!
I don't think it's possible to not sound creepy because schools have engraved in the minds of their students that people online are generally stalkers.
I agree with the person who said add them as a contact first. If you are an adult though, please don't add any kids or you WILL be a creeper. You could also look on your other friends' friend lists on facebook and see if you know any of them or want to be friends with them. If you don't know them or they don't know you they can see that you have a friend in common and you wont seem creepy.
Stalk Them I Guess And Based On Their Answers Talk To Them In A Manner That Will Appeal And Chat With Them Then Ask Them Is There Is Another Way To Contact Them (FB,Twitter,etc)