Introduces regex from simple concepts to abstract concepts. This article will help you to master regular expression quickly.
DEELX is a regular expression engine for C++. It is written in pure C++, and can be compiled by most C++ compilers.
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.