Here is a link for a step-by-step article on how to configure Database Mirroring using SQL Server 2008

You may need to check whether you need to configure database mirroring between stand-alone machines or in a cluster environment, whether an automatic failover is required or not. Also is the mirroring needs to configure between two different sites, if yes, then you may need to reconsider the operating modes as well.

Hope, this may help.