To get a vanity URL (www.facebook.com/yourproductname) you need to get 25 "likes" but then be very very careful
Once you get to the point where you want to choose your fan page name be careful not to attach to your own personal account. Once its been used its been used and there seems to be no way back to attaching it to another page or account.
This seems a bit inflexible of facebook but with millions of users I guess its understandable.
If you need help with use of facebook pages do give me a call or drop me an email.