The Opera Dev Network article on what Opera Mini on the iPhone means for developers has been updated with a new user-agent string for Opera Mini on the iPhone:
Opera/9.80 (iPhone; Opera Mini/5.0.0176/764; U; en) Presto/2.4.15
The user-agent string is the text string a browser uses to identify itself when connecting to a site. The site can then serve different content to different user-agents (browsers).
What this means for users of Opera Mini on the iPhone is that the sites you visit are more likely to send you pages formatted for the iPhone rather than the desktop version or a generic mobile page.
The old string was "
Opera/9.80 (J2ME/MIDP; Opera Mini/5.0.0176/1150; U; en) Presto/2.4.15".