LaTeX PDF Package Manuals and Guides

Most of these PDF files are available from http://www.ctan.org/, possibly in Postscipt or DVI format.

A very helpful guide for producin PDF files (including ones will nice clickable references is available here

LaTeX General/
General guides to LaTeX, including introductory guides.
Not so short LaTeX Guide
The excellent "Not so short LaTeX Guide"
LaTeX User Guide for Authors
Guide from the LaTeX Distribution
pdfTeX User Guide
Guide from the pdfTeX Distribution
LaTeX Primer
The Indian TeX Users Group LaTeX Primer
AMS LaTeX/
American Math Society (AMS) LaTeX Extensions.
AMS LaTeX Manual
Manual of the American Math Society LaTeX Extensions - recommended for maths typesetting
AMS Theorem Package
provides theorem, remark etc environments.
Quick ref cards/
TeX, LaTeX and emacs quick reference cards
Maths symbols
Contains most of the symbols LaTeX can produce.
AMS LaTeX ref card
Comprehensive LaTeX reference card geared towards AMS maths
AMS TeX ref card
An AMS TeX (not LaTeX) reference card
emacs ref card
Includes the keyboard short-cuts - good if stuck in text mode!
packages/
Useful packages manuals
authorindex
Produces an author index.
booktabs
Produces "publication quality" tables in LaTeX
beamer
Produces good quality slides in LaTeX (competitor to Prosper)
calc
Allows arithmetic to be performed in LaTeX
captcont
Allows the retaintion of figure or caption numbers across different float environments.
geometry
Makes changing margins, headers, footers etc much easier.
graphicx
Package for including graphics.
hyperref
Allows you to created PDF files with hyperlinks.
ifthen
Provides "if", "then" etc facilites for LaTeX.
keyval
Provides a the ability to write commands with named parameters (used in creation of packages).
mathclap
Not actually a package, but explains how to stop LaTeX allocating horizontal space (like a horizontal \smash).
pdfscreen
pdfscreen
prosper
Creates slides for using LaTeX.
Making Powerpoint-like Presentation with LaTeX.
prosper example
prosper introduction
prosper tour
psfrag
Replaces Postscript text within a postscript file - good for labelling figures.
rotating
Provides rotating features. It is better to use graphicx to perform this functionality if possible.
somedefs
A toolkit for package programmers.
subfigure
Allows nice presentation of subfigures.
supertabular
Allows advanced tables (eg split over a page).
tabularx
Allows automatically sized column widths in tables.
verbatim
Allows text to be entered verbatim.
xspace
.
bibtex/
BiBTeX - referencing index system.
bibtex manual
Users guide to BibTeX.
bibtex style design
Guide to creating/edit BibTeX styles.
harvard bibtex style
Guide to the Harvard family of BiBTeX styles.
natbib
Natural sciences citation styles.
misc/
Other useful manuals
epslatex
General information on the inclusions of graphics in LaTeX - very useful.
symbol list
A comprehensive list of all sybmols LaTeX can produce.