>Can anyone point me to a good documentation of the Berkeley Packet
>Filters? Reading other people's source is not a strength of mine,
>that's why I am looking for a book, web page or any other document
>that describes how to program them in detail.

The two best sources of information about them I've found are the bpf man
page, and the Usenix white paper (should be able to find it on ftp.ee.lbl.gov).

--Ken