Or maybe just try ctrl-alt-f1 to get a command prompt.....
Or, reboot and go into edit mode when grub comes up. Add "single" (without the quotes) to the kernel line and hit "b" to boot. This way, you do not have to go back and change the inittab again.
Note that your issue MIGHT have been caused by trying to set a resolution that was not in your /etc/X11/xorg.conf file---or that something else in that file is not right.