Here are a few SDR radio information links. I will add more as I find them or other people recommend them:
Wikipedia link to SDR : http://en.wikipedia.org/wiki/Software-defined_radio
A blog about RTL-SDR (RTL2832U) and cheap software defined radio: http://www.rtl-sdr.com/
SDR Radio roundup listing of Radios (dated - 2014): http://www.rtl-sdr.com/roundup-software-defined-radios/
Getting started with SDR# : https://www.rtl-sdr.com/sdrsharp-users-guide/
Listen to some SDR radios around the world: http://websdr.org/
More great SDR radios around the world: https://www.sdr.hu/
Ham Radio Science - some good SDR info: http://www.hamradioscience.com/
SDR Transceiver.com is a brief overview of several SDR transceivers on the market:
Very Good SDR book!
The Hobbyist's Guide to the RTL-SDR: Really Cheap Software Defined Radio
This book is a collection of articles from an internet blog, along with many added lists of softwrae and other SDR resources. It is from the authors of the RTL-SDR Blog and has detailed articles on RTL2832U RTL-SDR as well as other SDR's.
SDR software links:
THE BIG LIST OF RTL-SDR SUPPORTED SOFTWARE: http://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/
SDR # (sharp) - SDR software that works well with the RTL-SDR dongle: http://sdrsharp.com/
Using SDR # software with RTL-SDR dongles and other Software Defined Radios can seem complicated. I personally struggled with finding guidance on how to optimize the many parameters in the SDR# software.
Well I found a link to a great blog posting that does a nice job explaining many settings in SDR#. Find that blog post here: http://tylerwatt12.com/tips-for-using-sdr/
Using SDR# is pretty cool once you understand the settings and get them adjusted properly. So don't give up on SDR# or your dongle without trying some of the tips in this article.
Nooelec software (downloads tab) help page SDR # Auto loader (works very well!):
SDR-Radio.com SDR Console software and general SDR information: http://www.sdr-radio.com/