Air Sharing (via Mark Grimes) is so far the best iPhone application I’ve seen for making the iPhone show up as a disk in the Finder. The viewer supports all the expected file formats, including Web archives, and it remembers the document scroll position between viewings. The interface and help are very well done.
The only problem I encountered was with the Bonjour support. It uses the actual phone name set in iTunes, but says it’s using iPhone.local. And I couldn’t get it to work until I renamed my iPhone (“Michael Tsai's iPhone”) to remove the apostrophe.
Update (2008-09-11): The developer replied to my e-mail and said that these bugs are fixed for the upcoming 1.0.1 release.