There is a new DWG iFilter from Ransdell & Brown, Inc.

Go to http://www.dwgindex.com/DWGFilter.html  

 

The iFilter product will index text in AutoCAD DWG files (all versions, including 2010) on a variety Windows search technologies.  Native 32-bit and 64-bit installations are available for XP, Vista, and Windows 7, Windows Server 2003, and Windows Server 2008.  The following server products are supported: Office SharePoint Server 2007, Exchange Server 2007, Search Server 2008, SharePoint Services v3.0, SharePoint Portal Server 2003, SQL Server 2005, and SQL Server 2008.