Nifty little menulet to indicate which graphics card is active: displays an "i" for Intel's IGP and an "n" for nVidia (GeForce GT 320/330M). Also shows dependent processes, if the nVidia card is active. This is strictly for the new Core i5/i7 MacBooks Pro:

Not listed at versiontracker as yet, but here's the macupdate link to view current comments.