Dell Canada's Business group is having a "7 Days of Deals" promotion, and today they're offering the Dell Axim X50 for $336, a full $163 off the normal price:
They're also offering the X50v for $463. All prices are in Canadian dollars, and this offer will be over at the end of today. I believe that you'll get a free copy of the Windows Mobile 5 upgrade when it comes out as well. Act fast!