Need a little honest advice on what to do..... sometimes think friends are always too nice!

Basically, I met a guy through him coming into my work on the odd occasion related to work.  Each time he's been in he's been really chatty and has asked how my holidays been, commented on me getting my hair done etc. Not sure if he's just being nice or if he likes me.

I'm really shy and never would have approached him, not sure even if he was single until I saw him recently on a dating website. About a week later I plucked up the courage to leave him a message but he'd removed his profile.

Really not sure what to do as firstly, i kind of need to wait until the work issue is out of the way first or it may make things quite awkward, however this may not be for a few months.  Thing is, he seems like a lovely guy and I want  to let him know I'm interested but I'm really not sure how as I don't know when he'll be back in my work, don't have a phone number for him etc.

Any advice? Would it look stalkerish if i left him a message on facebook or would you think that was kinda nice? Should I wait and see if  he approaches me?