Though it was previously revealed that Google was working on and offering an iPhone targeted search as part of their User Distributed Search project, Google is now seemingly suggesting that iPhone users use their standard mobile portal instead of the UDS search offering.
Assumably through a user agent check, users visiting the Google home page from their iPhone are
now prompted as to whether they'd like to search and view results using the classic Google interface, or the mobile optimized version of the same service.
This is a feature of Google's site that was already in place for many other devices, but until recently, was not presenting such options to incoming sessions using the Mobile Safari browser found on the Apple iPhone.Unlike the AJAX based iPhone-specific UDS interface, the Google Mobile interface (http://www.google.com/m) offers a more typical Google experience. Results returned using the UDS interface (which is presumably still in some sort of beta state) are only optimized for the iPhone on the first page of results after which the browser is forwarded to the classic Google site for further paging. Google mobile search allows users to page through results as they please, while continuing to optimize output for mobile browsers.
Whether Google plans to back off the UDS iPhone search portal, and simply offer the standard Google mobile interface to iPhone users from now on, is unclear. For the time being, however, Google seems to think that Google mobile search is the best option for those looking for mobile optimized search results.