Mobile search engine Taptu, which calls itself an "alternative search machine," has launched an iPhone specific search engine. It crawls the web for pages and sites that are optimized for the iPhone and iPod Touch devices specifically. There are no links returned in search results. Instead you get preview "cards" or miniature pages that you can flick through or horizontally scroll through -- very much like the Palm Pre experience.
There's also a cascading menu to refine the search result by content source or to enable related searches.
Here's a video showing Taptu in action on the iPhone.