UltraTex emacs mode
For BibTeX data: K-theory file, Google scholar, and/or MathSciNet.
Useful: dvips -p 12 -l 24 myfile; ps2pdf myfile.ps
About hyperlinks: http://en.wikibooks.org/wiki/LaTeX/Hyperlinks
GmailTex is a Chrome extension for tex rendering in Gmail.
nLab page on LaTeX