Michael Levine's macro package for drawing Feynman diagrams in LaTeX is available in macros/latex209/contrib/feynman
Another possibility is Thorsten Ohl's macros/latex/contrib/supported/feynmf, that works in combination with METAFONT (or MetaPost). The feynmf or feynmp package reads a description of the diagram written in TeX, and writes out code. METAFONT (or MetaPost) can then produce a font (or PostScript file) for use in a subsequent LaTeX run. For new users, who have access to MetaPost, the PostScript version is probably the better route, for document portability and other reasons.