FunBrain.com has a lot of educational games that can go along with many different lessons and subjects. There are also web versions of books that have interactive "pages". This would be great for reading skills groups, and test review!

Acoustica.com allows you to mix multiple sound effects together to create your own sound. This would be great for reading books aloud and using descriptive sound words. This can also be useful for learning the different sounds that animals make. 

Teachnology offers multiple timeline templates, and is very user friendly. Just type in the information you have, and it will generate a timeline. Blank timeline templates are also available to print out which could be very useful for any history lesson, or timelines for books.