Warning: Hardcore geek stuff ahead! Ok, it’s not that bad, but it is very technical and of interest mainly to programmers.

One of the most powerful tools a programmer has is regular expressions… small bits of code that can examine a string and pull out all sorts of information. Here’s a tutorial on eight of the expressions every programmer should know:

8 Regular Expressions You Should Know – from nettuts+

I like how they color code the expression and explain what each part does. It really makes it easy to understand.