It seems that the terminal does not recognise CTRL+ALT+2 when typed, so I don't know how to quit the QEMU emulation, or switch to the QEMU control panel.
I am running Mac OSX Lion, and I type
$ qemu-system-arm -M verdex -pflash flash.img -nographic -sd sdcard.img
to start QEMU emulation of an ARM system in the Terminal. I learned from this site that typing CTRL+ALT+2 should work, but the only thing that happens to me, is that a "2" is printed on the command line of the virtual operating system. Any ideas on what could be wrong? Is this a Mac specific issue? (The same problem occurs in both terminal.app and iTerm2)