Xsights offers a different take on the whole "augmented reality" hoo-ha. Rather than a live-video overlay, it works by snapping a pic of a static image, then churning away in the background before popping up related info. Kind of like those price-comparison apps, but not limited to a barcode. (This Flash demo explains the entire process.)
That's the theory, at any rate. The (un-augmented) reality is that, unless the content's already in place through interested third parties, you're not gonna get much.
In all fairness, Xsights is still a startup, and their iPhone app's a downloadable beta (Blackberry and Sony Ericsson flavors are Due Momentarily), so we'll withhold judgement for the nonce.