The vinyl decals I ordered from SpeedySigns.com arrived today. It's pretty easy to apply them - I don't think it took more than half an hour, if that.
The decal letters come sandwiched between an opaque backing paper and a transparent sheet of sticky plastic. You clean the area where you want to put the decal, spray the area with a water & dish washing soap mix, peel off the opaque paper, and stick the decal on. You squeegee out as much of the soapy water as you can, then wait a few minutes. Then you slowly and ever so carefully peel off the transparent plastic.
You can see in the pictures that the pilot side has already had the transparent layer pulled off, while the co-pilot's side has not.
I think it looks pretty snazzy!