You can find the current edition of the rules at the games workshop us site:
http://www.games-workshop.com/gws/home.jsp
On that page you will see a bar with tabs. Look under the one that says [specialist games] scroll down to [Blood Bowl] when that page comes up look on the left at the bottom where is says Blood Bowl resources. Click this and the pdf files will come up. In order to play the game you must read
BB Completer Blood Bowl Rulebook.pdf
BB Rules Review.pdf
The rules must be taken from the GW site. There are allot of bastardized rulebooks out there, but these are the ones we use.