The boys (and gals) at Microsoft have finally released SP 3 for SQL 2005, finally no more installing SP2 and hotfix X (think they got up to 10) to prevent the distribution database growing in size after installing SP2.
You can find out more about the release at http://blogs.msdn.com/sqlreleaseservices/archive/2008/12/16/sql-server-2005-sp3-released.aspx but please remember never to install directly onto live servers without reviewing the new features and testing heavily.