A listing of licensed baseball bats approved for use in the Little League (Majors) Division and below can be found here: 2011 Approved Non-Wood Bat List (PDF)  (The list is updated periodically by LL.)

Wooden and aluminum metal/alloy bats are not subject to the moratorium. Bats that have only a metal or alloy barrel (and no other material, unless it is in the end cap of the bat), and if it meets the other standards (length, diameter, etc. for the respective division in which it is used) are not subject to the moratorium, regardless of the composition of the handle or the transition to the barrel.

“The moratorium is not the result of Little League changing its bat standards, or influenced by any relationships with bat manufacturers,” Patrick W. Wilson, Vice President of Operations at Little League International, said. “Rather, it became evident through scientific research, that some composite-barreled bats exceeded the current standard after a breaking-in process. Until that research was in hand there was no data to support an earlier decision. With that said, there are no other moratoriums contemplated at this moment.

“The decision to place the moratorium on composite bats in Little League’s baseball divisions is based on the fact that scientific research showed that composite-barreled bats may exceed the performance standard after being broken in.”

Note: The moratorium does not affect any Little League Softball divisions.