Since sharepoint is resource intensive, it would be better to stop the services when we are not using it.  The following URL contains some powershell scripts for starting/stopping sharepoint 2010 services.  I will modify these scripts for sharepoint foundation and post them soon here…

http://blogs.msdn.com/emberger/archive/2009/11/16/stop-and-go-with-sharepoint-2010-on-your-workstation.aspx