All you have to do to share your files with other computers on your network is enable this feature in your iPhoto preferences. In the Sharing tab of your iPhoto preferences, you can choose to share your entire Library or only individual albums. You can also assign a password to the shared albums. Other users on the network will need to know this password if they want to view your shared photos.
You can also set your preferences so that your computer looks for shared folders on other computers on your network. Any shared folders that are available in your network will be displayed in the source list after you enable this feature and close the iPhoto preferences window.