Apple just released updates for Logic and Mainstage. Logic Pro 9.1 and MainStage 2 are updates to Logic Pro 9, which is part of the paid upgrade to Logic Studio (2009). Both updates feature support for 64-bit native mode and compatibility with 64-bit Audio Unit plug-ins.
About the Logic Pro 9.1 update
This update improves overall stability, provides numerous fixes and enhancements, and is recommended for all users of Logic Pro 9. Running Logic Pro 9.1 in 64-bit mode requires Mac OS X v10.6.2 Snow Leopard, or later. For information about running Logic Pro in 64-bit mode, see this article.
MainStage 2.1 Update
This update improves overall performance and provides numerous fixes. This update is recommended for all users of MainStage 2.