Octave-Forge: CategoryLinks

See CategoryCode for individual subject areas.

Links to code and docs

http://www.octave.org
http://octave.sourceforge.net
Google for "octave" + TERMS of interest
Google for "matlab" + TERMS of interest and then apply the results to octave.
Lots of code gets posted on octave mailing lists, subscribe to all of them: http://www.octave.org/archive.html
Joao Cardoso's mailing list highlights (http://www.fe.up.pt/~jcard/Octave_links.html)
[BIOSIG] - an Octave/Matlab toolbox for biomedical signal processing
Octave to C++ compiler. It's still in an early phase, but the documentation also provides a nice discussion of the internal workings of Octave --> http://www.stud.tu-ilmenau.de/~rueckn/

Comparison of mathematical programs for data analysis: http://www.scientificweb.de/ncrunch/

http://scigraphica.sourceforge.net/
The R Project for Statistical Computing (http://www.r-project.org)
http://ftp.llp.fu-berlin.de/lsoft/index.shtml is the German "Scientific Applications for Linux" site -- the American and British sites seem to have gone out of existence. When this link was originally set -- it was a good starting point for scientific applications,
http://www.gap-system.org/ (GAP 4, which, BTW now GPL'ed), has tons of math stuff in the libraries.

Scilab (http://www.scilab.org) --- license: noncommercial use only, has a self-replicant clause and a BSDish clause too.