I found a partial solution here: http://linux.die.net/man/4/radeon
(for ATI cards)
If you look at the X-Windows manual, there are settings to put in xorg.conf for dual monitors and Xinerama. The only way it worked for me, however, was with the ATI radeon settings.
I have not found how to make laptop function keys work.
One thing I just stumbled across: OpenSUSE 10.3 has a GUI control panel for setting up multiple monitors---first time I have seen this on any distro.