Latest iPad SDK Contains Wikipedia Search Option
According to iPodNN, the current iPad SDK contains additional search options that allow you to choose Wikipedia as one of the default search engines for Safari on the iPhone, iPod touch and iPad. The reference is buried in the code of the iPad SDK, alongside the two other search options. While Safari defaults to Google at present, users can also toggle Yahoo search for a different set of results.
One current theory is that Apple may be veering away from Google, which it hasn’t been too happy with of late. The Wikipedia option, if chosen, would not link to outside web site, but rather articles within the Wikipedia database.
Evidence of Apple switching over to Microsoft’s Bing search engine has yet to appear, though this might be likely to change in the near term.