Extending display with second monitor

Question

I am trying to add a second monitor to expand my desktop area. I routinely do this with my G5 laptop by simply plugging in a second monitor, clicking on DISPLAY in SYSTEM PREFS, clicking ARRANGEMENT, and clicking off MIRROR DISPLAYS.
With the iMAC G5 ARRANGEMENT does not appear as an option and default seems to be mirror. Any way to make this work?

Answer 1

This is an update to my previous post. I searched on Google about this problem and found an answer -- an old Macworld article:
http://www.macworld.com/article/39969/2004/10/imacscreenspanning.html
It describes a freeware program called Screen Spanning Doctor. I printed out the page and followed the instructions. It worked! I now have a Samsung SyncMaster 930B set at 1280 x 1024 and my iMac G5 set at 1440 x 900 (maximums for both) and They are not mirrored; the Samsung monitor extends the desktop of my iMac G5. I couldn't be happier.
Just in case Screen Spanning Doctor does not work for you, be sure to print out this Apple support document, Resetting your Mac's PRAM and NVRAM:
http://support.apple.com/kb/HT1379?viewlocale=en_US
You can never be too careful. I believe what this will do is undo whatever changes Screen Spanning Doctor does. Per the Readme:
"This program is intended to unlock some features of the graphics hardware in some Macs (iBook, iMac, eMac but not for all models - you can find a complete list at my website http://macparts.de/ibook). On supported Macs it will allow the use of an extended desktop where usually only mirrored mode is available. This enables you to use an external display to extend your workspace. It will also unlock additional resolutions for the external display making it possible to driver high-resolution screens. This is especially nice if you want to use an LCD panel that has a higher native resolution than the 1024*768 of the internal display. After you apply the patch you should see an additional tab in the displays prYou will only see this tab if you have at least the monitor adapter plugged in."
Good luck! (I'm going to make a donation to macparts.de, which created this program. I figure it's worth $19 -- what I paid for the VGA display adapter at the Apple Store.