The new Serial Framework has been released.
Basic features- Enumerating serial devices (COM ports and Modems)
- Monitoring changes in serial hardware
- Exchange data with serial device
- Receive COM events
- Receive Modem events
- Full Serial Port control
- Support for Bluetooth vCOM
- Support for USB vCOM
- Support for com0com
http://www.btframework.com/serialframework.htm