There are many, many other web sites you can use to search Flickr photos. Among them are:
You can search by text or tag, within Creative Commons licenses, and with a safe search option. This would be a good tool for finding a photo to use in a project that will be published on the web. Don't forget to note the photo credit information to include in your own work.
Search by tag, and see the results as photos, and a list of tags with which to refine your search. This would be a great tool to teach search skills, and refining a search string, because the changes in results are so easy to see.
photo credit: http://www.forestandthetrees.com/findr/findrsnap.gif
Flickr Related Tag browser
This is also a great tool with which to teach search skills. Enter a tag, and suggested refinements appear as a circle around the original word, along with a small sphere of photos
FlickrStorm is my favorite tool. Before you enter your search term, click on "advanced", choose a Creative Commons liscense that will allow you to publish your work. Then enter your search term, and click "Search". As you select photos from the search return, a larger image opens on the left, and under the picture you have 3 options: "Open on Flickr", "Add to tray", and "Download". If you click "Add to tray", you will build up a collection of photos. When you're finished,you can download your collection, complete with photo credit information.
David Jakes has created these fine pdf filesyou can download: FlickrStorm Tutorial
Multicolr Search Lab
Here you search by color (up to 10), not tags. This is a very interesting tool, intended for web designers, but with interesting possibilites for language learners, art students, etc.
Visit these older posts about using photos from Flickr: Keywords/Tagging
Using other people's pictures in your work