These instructions are an elaboration on those found on the Debian Woody Post Install Instructin Pages. Those instructions are good, but I decided to detail the absolute easiest way to do it. People who want complete instructions should go visit the Kernel Howto.
First a few words of caution. I don't really know what I'm doing, but what I did seems to have worked for me. I tried the install out on a spare compter, and I suggest you do the same at first. In fact, I did this as a lazy way out of foul up. Don't do on your one and only, it's got eXPensive hard to install software and irreplacable, unbacked up work files and pictures of your baby girl. You can compile kernels on such a machine, but don't try putting installing one there untill you have taken care of business. Chances are, you will have no trouble and be very pleased with how things go, just make sure you don't get hurt if bad things happen.
You have to love the Debian way. Their method makes kernel compiling as easy as knowing the devices in your computer and installing a binary package. The Debian way makes it easy to compile and install kernels for all of your computers without too much risk. The end result is a kernel package, just like those found on debian mirrors that can be installed with the debian package manager, dpkg. The first time you do this might take you a few hours, so I've broken the process into three easy steps you can try after work:
Ready? Here we go: