I have not had a chance to try this one out myself so take this at face value. Slifter just released a BlackBerry application with a pretty interesting feature set. It helps you find products and deals based on your current location. You can just search for a product and find a promo or deal. It also seems to be a great tool for doing some comparison shopping if you want to see the going price for a certain item in your neighborhood.
Check it out by pointing your BlackBerry to www.slifter.com