Pocketop, the maker of a nice little infrared folding keyboard, has just released Symbian drivers that support the Nokia 3650, 7650 and Sony-Ericsson P800. I downloaded and installed the drivers and it mostly works OK. It requires that you run an app which listens on the infrared port.
While testing, I managed to lock myself out of the "General Settings" for the phone; I would just get an "App Closed gs" error :-(
Some folks indicate that the phone must be reinitialized (losing all phone data) to fix this. This is NOT the case. All that is necessary is to delete the "C:system.ini" from the phone. Then shut down and restart the phone.