What specifically are you trying to do? Use existing fonts in TeX, or create your own? And text mode or math mode?
If all you're looking to do is use an existing font in text mode, I can highly recommend fontools' autoinst script (http://www.ctan.org/tex-archive/fonts/utilities/fontools/); installing OpenType fonts with this script actually just works (believe it or not), and you get access to all of the OpenType goodness present in these fonts--text figures, small capitals, weight and width changes; the works. autoinst doesn't do anything about math mode fonts; they're a black art that I haven't had sufficient need to figure out yet. autoinst also only works for OpenType font, which has never been a problem for me; I vastly prefer OpenType format for all my fonts anyway.
If you want to make your own fonts and use them in TeX, I would recommend just crafting an OpenType font in FontForge (or FontLab, or whatever you can get your hands on), and using autoinst above to import it as a text font. But, again, this won't work for math fonts. I suspect just adding a math symbol or two would be fairly easy, but every symbol I've ever needed has already been created by someone else (just look at them all!).
Whatever you do, you'll probably need a copy of The LaTeX Companion, second edition (if you don't already have it). My poor copy isn't that old and it's already starting to grow dog ears....