Apple have released a MobileMe gallery app for the iPhone and iPod touch, that gives subscribers to their cloud storage and backup service easier access to their online galleries. The app - which is a free download from the App Store, but which obviously requires a MobileMe subscription in order to use - supports the usual pinch-zooming and swipe navigation on the iPhone, as well as basic offline browsing functionality.
Basically, as long as you've looked at the gallery once, you can subsequently view it even without a data connection (whether WiFi or cellular); presumably Apple keeps the local caches once they've been downloaded the first time, which should also speed up later slideshows. It's also possible to share photos and galleries via email, together with browse other MobileMe users' galleries.
The MobileMe app for iPhone allows access to password protected and hidden galleries, as well as public ones, and supports landscape and portrait orientation. So far there's nothing in the way of social network integration - we'd like to see any easy way to upload images to Facebook or share them on Twitter - but it's early days yet, we suppose. The app is available to download now [iTunes link]; MobileMe currently costs $99 per user per year.