"2 Key Transponder"

Nothing to worry about - it means that currently your vehicle has two keyfob transponders associated with it. Not knowing the year of your vehicle, I can't tell you exactly what you did to get this message, but on my 2002 9-3, if I push the "trunk release" button while the key is in the ignition (maybe just when it's on ACC or ON, I can't remember), this displays.

Useful when test driving a used vehicle, it will tell you if there's anyone out there with a keyfob that can open your vehicle!