Comment 34 for bug 418470

like alexander pointed out,
here a bit more detail (and a fixed typo):

acces a terminal and type: xinput list
find the joypad's id number.. mine is for instance 11

then type: xinput list-props 11
now look up the lines that say
"generate mouse events"
"generate key events"
there is a number behind those two.. mine are 713 and 714
those are the options numbers or like alexander calls them option-id
they are both set to "1" (on)

you dont want that so to set them to "0" (off)
to that you need to xinput set-prop <device-id> <option number> 0
so i'n my case i had to type:
xinput set-prop 11 713 0
and
xinput set-prop 11 714 0

hope this helps if you couldn't figure it out before

i still have to do this on my ubuntu 10.04
wich sucks.. is there a way to set this permanent?