I've installed xmonad in a debian vmware vm on osx. In Gnome I changed the screen resolution to 1440/900 using the GUI menu but this change did not affect the resolution I get when I'm logged in with xmonad as the window manager. I'd really like normal screen resolution in xmonad. How can I make that happen? Change a config file? Do something on the commandline?
I finally found out how to do this (for one session, I haven't figured out how to keep the change when I log out yet):
Log in with xmonad. Open run terminal (shift+alt+return). Write: xrandr -s 1440x900 then press enter. 1440x900 is of course the screen resolution.