Apple today released a slew of updates to their product suite, which included updates to the iLife product. Including in this update is a brand new iPhoto which features direct integration with both .Mac (which it had before) and the iPhone (which it had, but only basics). The update gave the ability for the iPhone to upload directly to the new-fangled Web 2.0 ish photo interface on your .Mac account.
When you take a picture on the iPhone, there is now an option to upload to a Web Gallery. This feature only appears if you have your .Mac account setup on the iPhone. Do note that this setting took a few hours to appear on my iPhone.
It appears that you also need to have Upload via E-mail enabled from a gallery that you publish to .Mac through iPhoto for this feature to work.
It also appears that it only uploads the VGA versions of photos, not the full resolution one. The ability to upload full resolution photos from the iPhone is still missing (sadly).
For an example of one photo uploaded through iPhoto (from Photobooth), and one from iPhone, check My new Gallery, which I'll update periodically.