creating custom binary packages?

[Kit Peters]

I have a need to create my own .debs for a box at work, and I'd like to use precompiled stuff when I can.  How do I create a custom .deb from a precompiled package, a la firefox or MySQL?  I've looked at the New Maintainer's Guide (though perhaps not as in depth as I ought) and I didn't see anything there.  Can anyone give me some pointers?

Kit Peters