Well, you could of course use the full-screen consoles: C-M-F[1-6];
if you want to run a terminal within gnome, go menu -> applications -> system tools -> terminal (use arrow keys & enter to navigate)
if you don't have a keybinding for the menu, edit ~/.gconfd/apps/metacity/global_keybindings/%gconf.xml to contain this:
<entry name="panel_main_menu" mtime="1110573704" type="string">
(or you could use <Alt>F3, or whatever suits your needs).
Hope this helps,