The popular YouTube technology show Hak5 has recently been posting videos related to software defined radio and more specifically RTL-SDR. Two of their recent videos are about an easy to follow GNU Radio tutorial for complete beginners. In the first tutorial they show how to add an RTL2832U source in GNU Radio and output it to a FFT Sink. In the second tutorial they go further and show how to build an FM Receiver.
Building Software Radios With A Little Bit Of Python, Hak5 1526
Going Deeper Into GNURadio Companion, Hak5 1601