Public service broadcast:
Over on the stardot forums user Martin B has published code to bit-bang a serial connection at 115k.
Needs cycle-accurate code and a 2MHz 6502. It's an interesting thread with some good explanations of what's needed. It turns out that coping with all varieties of serial port is tricky. The overall goal is to make use of a Bluetooth serial adaptor for a wireless connection between PC and 6502.
6502.org
The 6502 Microprocessor Resource