http://www.bbc.co.uk/radio3/discovering ... hive.shtml
http://music.guardian.co.uk/classical/p ... 67,00.html
On these sites you can listen to podcasts explaining classical (piano) pieces. The first one features pieces of many different styles and eras. The second one focuses on Beethoven's piano sonatas, done by Andras Schiff. I find it very useful and sometimes quite funny.
If you know similar things on the net, please post them.
The ones by BBC need RealPlayer, while Schiff comes in usual mp3 format.