Amazon has replacement key fob shells for around $20. As long as the "guts" of the old fob work it is an easy job to replace the shell. This is a common problem with all cars that have rubberized key fobs; not a Saab-specific problem.
To @Mimmi's point, if you don't have at least two key fobs that work with your car then get a replacement fob ASAP and get it programmed. They are less than $100 new and programming takes maybe 15 minutes. If you lose your last fob then you're not going to be able to use your 9-3 until it gets a new CIM (expensive) installed and programmed.
Someone showed up at a tech session with an aftermarket fob or shell, I'm not sure which.
The fob worked, in that the remote did its thing and the fob unlocked the steering column lock. However, it could not turn in the ISM. Something dimensionally about the end you insert was off. I was able to turn on the car by holding the fob very close to the ISM and turning the ignition switch with my fingers.
We looked at the damn fob, and it looked fine. We couldn't tell what the issue was. But it wouldn't turn.