I recommend SpareRoom as the best source for finding tenants and spare rooms any chance I get.
I would just like to say that thanks to your fantastic website I have managed to find somewhere else to live.
Advertised room in shops, local rag etc No joy! Advertised here and had 5 responses in 3 days. I mailed back 1st person and he moved in 5 days later. Brilliant, hassle free and will use again for future rooms... cheers