I’m also looking at SAGE, Software for Algebra and Geometry Experimentation, a free mathematical programming system using Python + a lot of open source tools. On Windows, SAGE requires VMWare and uses firefox. You can use it online, but so far it’s rather slow, and appears to have been slashdotted.
Impressive tool! Feels a lot like Mathematica, accessible via web browser. The tutorial is well-worth running through (I used the on-line version while upgrading my local install, but the local version allows you to run the calculation cells using Shift-Enter ).
Adding dvipng SAGE package requires adding ghostscript, via apt-get
Also requires libkpathsea, which requires tetex via apt-get install tetex-extra
PostScript: the SAGE dvipng package doesn’t work, but apt-get install dvipng puts dvipng on the system, which should suffice.
PostScript: SAGE can be upgraded to Gutsy, I used the Upgrade Manager available in Xubuntu (I wanted a GUI for some SAGE file management via apt-get install xubuntu-desktop)
Doesn’t work yet on BSD, alas, and running a SAGE server has security implications.