Design: In a sea of web app splash pages from the past sixth months, your simple demo site is somewhat refreshing to me. With that said, I think you could improve a few things. The demonstration of the app could be more clear by making it linear (horizontal or vertical) as opposed to the 4 images -- which is kind of confusing at first..maybe arrows would help. I like the photo with the hand holding the iphone at the shelf, and the purple scheme :).

Idea: I may be biased, because I love these apps and think this space is ripe for innovation (shopkick/stickybits), but I really like your idea/concept. One issue I see, however, is that a player in this space is indeed ShopKick and your name, ShopSideKick, is very similar. Since your concept is pretty unique in scanning shelf barcodes instead of the product, why not own it with a completely different name/brand/concept? I know they work with Best Buy as well, so there are a lot of small similarities that can be immediately drawn between ShopKick and ShopeSideKick.

Also, since you have an application that is the "first" to do shelf scanning instead of the product, maybe it would be wise to put more emphasis on this unique ease-of-use in stores compared to other apps out there now (when promoting to businesses and consumers).

Hope thats helpful...