I've heard mixed results about people using Facebook ads. They are much like Google Adwords, so a good working knowledge about PPC and how it works would help you quite a bit before moving forward with Facebook ads.
Some people (mostly larger companies) report good results with FB ads but I've not generally heard the same for small businesses unless you can really get the attention of the your target market. Which unless you have a very specific market you are trying to reach, it may be hard to get the attention of just the general FB user.
If you do a search on
http://insidefacebook.com for Facebook ads, then you see several articles they've posted about how to use Facebook ads and if they work.
Personally, I've not recommended them to any of my clients to use because I'm not entirely convinced they are all that beneficial.