The Adventures of Penny Plastic is about a girl who lives reasonably but still has managed to accrue $22,000 in debt. She writes about why she shops, how she shops, and how she is cutting back on her expenses. It's fascinating and, as someone who definitely shops compulsively at times, good to know I'm not alone.
Step One: Keep a log of every purchase you make. It's definitely helped me. And while Penny doesn't like the website Mint.com for usability issues, I love the idea of it. Unfortunately, I just signed up and found out I've spent WAY too much money on clothes this month. Yikes.