Regex Tutorial
Introduces regex from simple concepts to abstract concepts. This article will help you to master regular expression quickly.
Regex Engine for C++
DEELX is a regular expression engine for C++. It is written in pure C++, and can be compiled by most C++ compilers.
Regex Tools
Tools to compose and test regular expression patterns, especially good at complex and long patterns, Regex Match Tracer, Wildcard to regex.
Regex Applications
Several regex applications, which use regex in practice. Such as syntax highliting in Word, web scrapping etc.
Regular Expression Laboratory
This is a site which do research and study on regular expressions. You can learn regex here, and you can also find useful tools and applications.