Share Keyboard Shortcuts
The best bet is to change some shortcuts while observing the content of your Preferences folder sorted by modification date.

In my system (10.7.5 Lion) the relevant files are com.apple.symbolichotkeys.plist, com.apple.universalaccess.plist and pbs.plist as well as probably somehow related plists like com.apple.systempreferences.plist/com.apple.ServicesMenu.Services.plist.

If both of your Macs have the same system/apps installed simply copy the files you found.