Hey Jenn -
There are 3 ways I do this. 1) if someone who is not actually friend or family member and they request to "friend" me I send them back a message and say - "Hi _____, thank you for your friend request. However, I usually keep the friend side for just family type stuff, and a few non-business contacts. I would love to invite you to go to my Business Fan Page and "like" me.

That way I can share relevant information with you...and also I will be sure to "like" you back! 2) If I don't get a request I basically say the same thing above in an email after I've met people...and I include a little brief re-introduction. 3) After I get 25 people "liking" me I'll be getting the web address on my business cards. Reason they aren't now is because of that long # that follows.
Key is to drive them there, just as you would your website, after you do what A Lynn suggested, which is to get a few posts (not more than 3 or 4), so that people will see all of them when your first bunch o' people show up. Then, write at least once every other day, at least for awhile.
Hope it's helpful!
Pam