Little League has just issued new guidelines for the use of composite bats. Effective January 1st, 2011 composite barrel bats are no longer allowed in any baseball division. All softball divisions are not affected. These changes are similar to changes enacted by the NCAA and High School Baseball.
You can read more at the following Little League Site: http://www.littleleague.org/media/newsarchive/2010/Sep-Dec/CompositeBatMoratium.htm