Microsoft has released Update Rollup 2 on Janury the 19th. This is a tested, cumulative set of updates for Microsoft Dynamics CRM 4.0. It includes performance enhancements that are packaged together for easy deployment.
For more information about this release, see Microsoft Knowledge Base article 959419.
Update Rollup 2 contains updates (32 and 64 BIT) regarding the server, client, router, data manager and SRS and it can be downloaded here.