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: 
I can't say for certain because I'm not using Debian but if you're using Gnome the easiest way is to run gnome-keybinding-properties (System > Preferences > Keyboard Shortcuts)

Instead of typing a shortcut such as `Ctrl`+`M`, hit the button on your keyboard.

If you would prefer to do this via command line or with a different desktop environment, this may help: [Unusual keys and keyboards](http://www.tldp.org/HOWTO/Keyboard-and-Console-HOWTO-14.html)
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.