creating a shortcut from a a key combo

[h.engemann at basicartstudios.de]

Hi,

is there a way to create a alias or shellscript from the <ALT>+<TAB> key 
combination?
I wanna set this to a custom button.

xev gave me this "keysym 0xffe9, Alt_L" after i pressed <ALT>+<TAB>.
I looked into the bash documentation but i couldnt find any hints.

thx
_.h