Since the release of the iPhone a number of sites including iPodia and Wapedia have released optimized versions of Wikipedia (though none actually made by the online encyclopedia). These sites reformat Wikipedia articles to better fit the iPhones screen while shrinking (or removing) images to conserve bandwidth.
What sets Powerset apart, and may make it the premier way to look up information from the iPhone, is the search engine’s ability to find both the relevant article and the exact passage that pertains to the search query. Even through the iPhone sports a relatively large screen, browsing through large amounts of text can still be a pain, which makes this feature even more valuable.
Powerset has lofty goals, aiming to use their natural search technology to overtake traditional search giants like Google. So far the company is only using Wikipedia for search results, so it’s hard to tell how well the technology will work once Powerset finally indexes the web, but for the time being it may well be the best reference tool on the iPhone.
You can watch a brief demo in the video below: