Apple support has confirmed that Mac OS X 10.6.2 may falsely display a “Service Battery” message on some MacBooks and MacBook Pros, yet the battery appears to behave properly. Rebooting on a regular basis should clear this message.  A fix will likely be included with the forthcoming Mac OS X 10.6.3 update.  Note: If you are actually experiencing battery problems, such as abrupt shut downs on full charge or a swelling battery, pursue replacing your battery under warranty or AppleCare.