I'm sure it's possible, there are plenty of w/a convertors around with standard screw threads. What the results would be like is anybodies guess. They're mostly designed for small sensor bridge and compacts and then only at the wideangle end of the zoom. So I suspect not very good.....
Better off buying a wide-angle lens methinks. A good wide-angle conversion lens is nearly as expensive anyway.
Do you have a budget?