I've been talking about Flickr with some of you who are interested in photo storage and showing photos to others. I use it to show additional photos that don't make it to the blog as well as a place to store photos so I have a backup. I found the script to add a flickr feed to the blog and it automatically generates thumbnail images from the photo set I selected. I'm still using the free flickr registration - so far I'm able to stay within the 20MB monthly upload requirement. But if it ever became a issue I wouldn't have a problem with paying the $24.95 for a yearly subscription.
A number of additional tools that work with Flickr are availabe and this list came via my co-worker Christen. Here's a blogposting (http://mashable.com/2007/08/04/flickr-toolbox/ ) that has additional Flickr tools that might be helpful when using Flickr and other web software you use. There's also some fun games you could create and play (or have your student's play)