Launch iPhoto by selecting its icon in the dock
Select an album or event from the iPhoto library.
Select Web Gallery from the Share Menu.
If you have not signed in to .Mac on this computer you will be prompted to do so. Click the Sign In button
Enter your dotMac Member Name and Password then click the Sign In button.
Select Web Gallery from the Share Menu again if required.
Select who can view the album from the Album Viewable by: dropdown.
iPhoto will publish your gallery to .Mac. Notice on the left side of the window your gallery name will appear under the Web Gallery section.
Select the newly created Web Gallery from the list on the left side of the window. You will then be shown the url for the gallery at the top of the iPhoto window. This is the url you would give to people so they can view your Web Gallery!