Cemonitor is a small PocketPC app that allows you to see the received NMEA sentences, but it also allows you to setup your GPS antenna (if it supports it). In this setup, you can ask your GPS to send data in NMEA or Sirf format, and you can also setup the sentences it will transmit to your Pocket PC. For example 1 GGA sentence every second, one GSV every 5 seconds,....
To summarize, The NMEA protocol is one way, but you can send data to the GPS receiver to configure it.
I will ask the programmers of the original extraction code if they allow me to use their code in my program. Then if they agree, I'll put it as free on the Internet. If they don't, I'll try to do the extraction part by myself.