Regular Expressions, where can I read about it?

Hi, I am trying to create a class to filter the data in&out the database, it is not easy since I have too many specific needs, a simple nl2br() won't help me at all... I am very bad in regular expressions, I need to learn much more about it before I actually start writing my class... Does anyone of you know a good tutorial on regex, like how to use it (not function or php specifically) , examples, ideas, manual, lists, codes... whatever.. Thank you, guys. Maxim Maletsky - maxim@j-door.com <mailto:maxim@j-door.com> Webmaster, J-Door.com / J@pan Inc. LINC Media, Inc. TEL: 03-3499-2175 x 1271 FAX: 03-3499-3109 http://www.j-door.com <http://www.j-door.com/> http://www.japaninc.net <http://www.japaninc.net/> http://www.lincmedia.co.jp <http://www.lincmedia.co.jp/>