Ever find yourself out shopping and think, "Hmm, I wonder if I should buy this thing now or would it be cheaper if I went home and bought it online?". Now you don't have to wait. Use your mobile phone, dial-into Amabuddy, and enter the product's UPC number. You'll get back pricing and rating information. This service's "real time price checks" are built on the Amazon APIs.
It's not alone in this space and competes with other, bigger mobile shopping services like Froogle, Smarter.com, and Buyscan.com. See this story in the Boston Globe for more details (but beware the annoying pop-unders).