http://wordpress.visitmix.com

This patch makes wordpress workable with MS Sql Server 2005, 2008 and Azure Databases

You may either download the entire wordpress + package or you may download the standalone patch and overwrite the files in your wordpress directory. If you do the later to an existing wordpress installation it is strongly recommended that you backup your database, config, the files to be overwritten, and also make a WP export of your blog (which you would want to import once you setup wordpress for your MS database).

These patches uses the mssql PHP drivers for Sql Server 2005, 2008 and you may also use the sqlsrv drivers to connect to a SQL Azure DB.

http://www.microsoft.com/sqlserver/2005/en/us/PHP-Driver.aspx