Tutorial: Creating a Granny Square

There's a few different ways to make a granny square and several generous people out there that have shared their time and talents to show others how to crochet granny squares.  Below is a list of resources from start to finish that can help you create your own granny squares.

(Keep in mind that many people have different ways of crocheting and no way is right or wrong)

Learn the Stitches

Chain (ch) by amyjdenham
Double Crochet (dc) by amyjdenham

Tips and Tricks

How to make a Magic Circle (aka Magic Ring) by ChemKnits Tutorials
Making a double crochet at the beginning of your round rather than a chain 3 with Moogly.
Seamless join (use this before finishing off) by Playin' Hooky Designs
Join as you go by WEBS

Basic Granny Square

Traditional Granny Square  (recommended if not using Moogly's beginning double crochet from above)
Crochet Crowd 
Crochet Cabana
The Humble Granny Square with pictures by Renate Kirkpatrick

Half Granny Square

Crochet Geek (made with magic loop and creates a triangle which two can be sewn together)
dontfencemein1979 (full square with multicolored half squares)

Afghan Sizes

Baby Sizes:
Lovey 10x10
Security  14x17
Stroller  30x35
Receiving 40x40
Toddler 42x52
Swaddle 47x47

Adult Sizes
Throw 52x60
Twin 59x85
Queen 90x90
Super Queen 96x94
King 108x90