You want to make sure to take a trip through the "SQL Surface Area Configuration" tool. Look for the tab relating to "remote connections", and turn on TCP/IP. In this case, remote = anything other than SQL Server itself....
Also - try making sure that the SQL Browser service is started.
----------------------------------------------------------------------------------
Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?