I just discovered a cool little tool/site, MimeTeX. MimeTeX, the tool, renders TeX formulas into GIFs. The program does not itself use TeX or TeX fonts, but rather implements a subset. MimeTeX, the site, actually allows you to generate GIFs from TeX formulas directly at the site. This might be handy for creating the occasional image for weblog posts.
CodeCogs has an Equation Editor which uses LaTeX to produce PNGs which can be used in the same way for occasional images.