As some of us know, on the late 2008 Macbook Pro you have to switch graphics via the Energy Saver in Preferences MANUALLY.
This small utility lets you switch based on what power source you use AUTOMATICALLY.
Just install it and check the "Use power source-based switching" under Preferences.
To top it off, my display blink problem under 9400m Energy Saver has been reduced from once every 3 min to ONCE every 6-8 hours, when using the above mentioned settings. YES!