Can't install - 'Xcode is not installed..'

[Tim Johnson]

FYI: Using OSX Lion on 2011 mac mini.
I am brand new to OSX and macs. 

I am a long-time linux user, programmer and comfortable with the
*nix command line.

I downloaded Xcode and installed it (or so I thought). Now when I
attempt to install macports I get the following error message:

"Macports-20.3 Can't be installed on this computer. Xcode is not
installed or was installed with UNIX Development (10.5+) or command
line support deselected."

I attempted to re-install Xcode but the installer would not proceed
because (sic) 'Xcode is already installed.'

Please advise.
TIA
-- 
Tim 
tim at tee jay forty nine dot com or akwebsoft dot com
http://www.akwebsoft.com