Please see here a video about automatic Doppler correction on RTL-SDR dongle with Orbitron as server and SDR# as client with Sattelite Tracking Plugin. QSOs on SO-50 on orbit #56000:

http://www.youtube.com/watch?v=K0iw7kpv0Zo

About Doppler and SDR#, see here:

http://www.qsl.net/py4zbz/rtldop.htm

73 de Roland PY4ZBZ