For those of you that don't know any CAS (Computer Algebra System), specially any capable of symbolic computations as well as numeric, here's a little
Maxima:
http://dl.dropbox.com/u/15818997/Maxima.mht
That link is a MHTML file, any browser should be able to open it I think, except for Safari and Firefox needs some extension.
This is free software, amazing. Too bad I didn't know it before. I could port my
Sun position calculator to this.