Apple’s MobileMe Gallery iPhone app offers the option to take over all gallery.me.com links. Enabling this option in the app will open a Safari page to confirm this option.
A clunky aspect of this feature is that tapping a Gallery link will open it first in Mobile Safari, then switch you to the Gallery app. If you click a link from, say, Mail, this means you first switch to Safari, then to MobileMe Gallery just to view the gallery. Apple apparently does not allow any other apps (including its own) to take over URLs at the system level, like iTunes is able to. Tapping an iTunes link in Tweetie, for example, will present a prompt to open the iTunes Store; it won’t bounce you around like these Gallery links.