Question: I have a Microsoft keyboard with a series of non-standard buttons such as "Mail", "Search" , "Web/Home" etc.

It would be nice to be able to bind these keys so they execute arbitrary programs.

Does anybody know how to do this in Debian Etch?

Answer: 
Running Debian, I had the same issue. What I did is run xev and see what keycode those keys return. Microsoft likes to break standards a little, so some of the multimedia keys just won't work. But the ones that do will return a keycode. Then write a script with xmodmap to map those keys properly. 

The [Gentoo Wiki](http://gentoo-wiki.com/HOWTO_Use_Multimedia_Keys "HOWTO Use Multimedia Keys") has excellent documentation on how to do these things.

I put my xmodmap script in ~/.kde/Autostart/ because I use kde, but you could just as easily put it in your home folder and have your .bashrc or .profile source it. 

Once you've mapped the keycodes, you can assign those keys to specific actions in your desktop environment.
There's a few different ways to do so, the easiest generally being [keytouch](http://keytouch.sourceforge.net/), which is probably available in the Debian repositories. The user manual is [here](http://keytouch.sourceforge.net/user_manual/user_manual.html). There is a chance that your keyboard won't work with it though.