What are the current rules and regulations regarding Slow Pitch softball bats?

There really aren't any universal rules for the game of slow pitch softball, so it's best to select the rule book of the organization governs your league below and read up on the current slow pitch softball rules. 

ASA - Amateur Softball Association
2013 Official ASA Code (PDF)

USSSA - United States Specialty Sports Association
2013 Official USSSA Slow Pitch Playing Rules and By Laws (PDF)

NSA - National Softball Association
2013 Complete NSA Rulebook (PDF)

ISA - Independent Softball Association
2013 ISA Rules and Regulations - Multiple Helpful Links

ISF - International Softball Federation
2013 ISF Official Rules of Softball (PDF)

SSUSA - Senior Softball USA
2013 Official Senior Softball-USA Rulebook (PDF)