Here is a list of useful radio related links :-
Airband
UK NATS (National Air Traffic Services) Frequency Reference Cards (click here)
UK Airband frequency list (click here)
UK Airband frequency list (click here)
UK Airband frequency list (click here)
Frequency Info (General)
Ofcom spectrum information portal (click here)
Frequency Info (HF Band)
HF pirate radio frequencies (click here)
SDR
List of public KiwiSDR's around the world (click here)
WebSDR in Netherlands (click here)
Software
SDR Connect (click here)
SDR Sharp (click here)