Some info on TDI filter drivers

Hi everybody,
Is there a place where we can get sources for a sample TDI filter driver
(e.g. lets say for filtering packets going between NetBT and TCP/IP
stack).
Or does it come with the standard MSDN distribution? Any suggestions
will help.
BTW, has anyone used the Microsoft Windows Server 2003 Installable File
Systems Development Kit. They claim that it has samples for TDI client
and drivers.
But it costs $995.
Thanks.