Making background transparent in image

[Joel Hammer]

Well, its working fine with staroffice.
But, if anyone knows the incantation to make the background transparent with
convert, please post it. 
It is supposed to be something like:
convert -draw "matte 2,2 floodfill" image.in image.out
But, this doesn't make the matte transparent, it makes it white, picking up
the background color at pixel 2,2. 
I must be leaving out some vital options.
Any insight appreciated.
Joel