O-K, Oberon Kompiler :)
O-K is an open source project to develop Oberon Language
Compiler should support at least Oberon, Oberon-2, and Oberon-SA
It is in early stage of development now.
I don't think it is reasonable to download compiler now.
It is not ready for work yet
SourceForge download page
Project has no dosumentation yet, only some implementation notes