There are some great algebra and geometry (and trigonometry, calculus, and many other topics all the way down to addition of 1 digit numbers) at www.lulu.com/roxlulu. Enjoy! (They are very nice because they are self-checking via decoders.)

They are not of a tutorial nature, but there are 3 very good worksheets on finding derivatives using various methods that self-check via a decoder at www.lulu.com/roxlulu All you have to do is download them. It's free! CALCULUS FOR EVERYONE!

I am not a sub, but substitute teacher friends of mine have found the self-checking worksheets at www.lulu.com/roxlulu to be very useful. The students get lots of support from the worksheets themselves because they are self-checking via decoder. (This also gives the kids a little extra motivation.) Topics range all the way from 1-digit addition to Calculus! MANY ARE FREE TOO!