I can't say Facebook has brought me business directly but it's helped in local networking in a huge way. There are some local "big players" on facebook... a couple of companies with 4000 + fans nearly all local to me so I work with them to link into their facebook pages and offer up donations (prizes) to be promoted on the site.
We did this guys deck - he owns valpolife and posted a review on his website as well as a link to the article on facebook. I "shared" the article which then was shared by about 4 or 5 other people (my insurance agent, some family/friends and whomever). The point being that article went across the wall of facebook to about 7000-8000 people by the time it was all done.
If I could do it again I would have made my facebook page timberseal.net and make it independent of my personal site so I could post to walls as timberseal.net. The only downside to that is people have to request friendship rather than just like your page.