I'm used to VS2008, in which a release build would be built upon pressing F6, or in the menu Build > Build Solution.
The build menu is gone, and although I can build the solution (through F6), it only builds the debug.
I assume there is some kind of configuration manager now, but I can't find it anywhere.
If you have no Build Menu in Visual Studio 2010 Express, go to the menu Tools -> Settings -> select 'Expert Settings'