FSK Demodulator

Hi

i would like to build a FSK demodulator. Does any body know where to get started?
any good links or hints. I think I could use an PLL circuit.... or something

thanks

Steve

There are examples of dedicated IC for FSK demodulation.
One of them is the XR2211.
http://www.exar.com/product.php?ProdNumber=XR2211

Added after 17 minutes:

Another option is the very popular NE564.
http://www.semiconductors.philips.co...tes/AN1801.pdf

how easy is this to buy?
know of where i can get a few?