Problem installing a program

[playm0de]

I am taking Physics online instead of at school next year so I can take a different class. For the class I need to download a program called Graphical Analysis. After I download the program, it appears as a .sit file on my desktop. After clicking it, a window comes up that says "choose program to open file"....what program do I use to open this with? Also, is it possible that the problem is that this program is just for the PPC macs and not for intel?

[puaerotch]

you may need to open it with stuffit expander. .sit files are compressed files, similar to .zip

[playm0de]

thanks! just helped me out a ton.