Load this file nokia.xkb into your Nokia X server using command
xkbcomp nokia.xkb :0.0and you can switch between latin (en-US) and russian keyboard layout via Ctrl+Shift key combination.
Note that Nokia N800 X library has annoying bug - it aliases ru_RU locale which is set by operating system to ru_RU.ISO8859-5, when rest of system supposes that ru_RU is ru_RU.UTF-8.
So, keyboard would switch, but no russian letters recognizable by applications would be produced in russian mode.
Fix this bug by editing /usr/share/X11/locale/locale.alias and reboot before testing.