Link Categories:
Applications Astronomy Astrophysics C++ Java Linguistics Spanish Tagalog

Applications (mostly freeware/open source)

Graphviz - Graph visualization software.
Tux Commander - Total Commander-like file manager.

Astronomy

American Astronomical Society
Astronomical Applications Department of US Naval Observatory
Astronomical Information Processing System++
Astroweb
Eric Weisstein's World of Astronomy
European Southern Observatory
Galaxies and the Universe - WWW Course Notes
National Optical Astronomy Observatory
National Radio Astronomy Observatory
National Space Society
Scisoft
SIMBAD Astronomical Database
Space Telescope Science Institute
The Astronomical Journal
UniverseToday

Astrophysics

Astrophysics Source Code Library
NASA Astrophysics Data System
The Astrophysical Journal

C++

cplusplus resources
SGI's Standard Template Library Programmer's Guide

Java

Java 1.5 API Documentation

Linguistics

My Language Exchange - Online community for learning and practicing tons of languages with native speakers.

Spanish

Diccionarios.com
SpanishDICT.com

Tagalog

Tagalog - Part of the SEAsite Project at NIU.
Tagalog at Omniglot - Tagalog alphabet, pronounciation, and language.
Tagalog Dictionary
Tagalog Learner's Home