Well I know Dominique Louis has written a pretty good tutorial on the basics of Isometric tiling/engine/maps and I found this site while searching on google, it has quite a few links on it to Isometric information :

http://www.isometrix.org/resource.htm

I know there should also be a FAQ on Isometric or at least on Tile-Based games and I know there is a book (well more than one actually) on Isometric maps...

If you are just starting to program graphics/games, I would suggest to read in on the library you want to use, since Isometric Engines are not easy to write!

And remember, google is our friend!