The other day I was trying to help a client connect to the Console Session on a Windows 2003 Server from their XP computer.  For some reason connecting via mstsc.exe /console they were not getting connected to the console.  What was odd was that from my XP laptop I had no problems.  I was ready to pull out my hair when I found an article on the Terminal Services Blog.  If you are using a remote desktop connection from a Window XP SP3 machine the /console is silently ignored.  Now you need to supply a /admin instead of /console.