The best of the photo hosting services is Flickr.

Here’s a friendly introduction to the service:

Flickr is a popular photo-sharing and hosting service with advanced and powerful features. It supports an active and engaged community where people share and explore each other’s photos.

You can share and host hundreds of your own pictures on Flickr without paying a dime. There’s also a pro service that gets you unlimited storage and sharing for about $2 a month, making it one of the cheapest hosting sites around (more on that later).

Newbie’s Guide to Flickr | Webware : Cool Web apps for everyone