Music software with 'assignable' qwerty keys??????

Hi.

Im trying to find a music program that lets me assign the computer keyboard keys to the notes. I used one waaaaaay back (can't remember the name) on the Amiga and kind of still remember the keys i had for that so would rather keep that setup witch is more intuitive than learning the qwerty keys any particular music program sets them as.
I downloaded a bunch of demos for programs but can't seem to find one that simply lets me choose what keys on the keyboard play which notes.
it doesn't have to be a feature packed program as all i want to do is tap out my own tunes etc on the keyboard so need to map my own key setup.
anyone know of one?