We're figuring a lot of folks will default to the ubiquitous YouTube for iPhone 3G S video sharing, since Apple was user-minded enough to include it in the options. But for those who want pristine QuickTime quality, the Mobile Me news blog has you covered:
The new iPhone 3G S lets you shoot video in addition to photos, and sharing those videos on your MobileMe Gallery works exactly the same. From your camera roll choose what you want to share — video or photo — tap the arrow in the lower left corner, and choose Send to MobileMe. Enter a title, choose the album you want to publish to, and tap Publish. (If there are no albums in your Gallery, one called "New Album" will be automatically created.) Click here to learn more about Gallery.
If you're sharing some iPhone 3G S video, let us know how you like the quality, and the MobileMe gallery uploads.