Hello,
>
> I've got my robot from robowatch.com and a AT9155800 microprocessor
> from Atmel. I know there is a GNU compiler for AVR, but I cannot find
> one for my ATM9155800. Can anyone help?
>
> I thank you all in advance and look forward to your responses,
>
> Brian
The AT9155800 is an ARM-based microcontroller, and is completely unrelated to the AVR (except obviously that Atmel makes them both). You are looking for a gcc ARM cross compiler. You can either build it yourself (it's standard for gcc), or get hold of pre-built binaries for the OS of your choice. Now that you know what you are looking for, googling for "gcc ARM windows", for example, will get you started.