90s or '00s Fiction Book About Hacking

I'm hoping someone has read this book as I'm trying to figure out the title to read again. It's a book about a courier who roller blade-delivers packages for his day job and has a small circle of hacker friends he hangs out with otherwise. One of the hacker friends is a gal with blue hair. I read it forever ago but remember it being a REALLY good book. Now that I'm getting into programming I thought it'd be fun to read again.

Anyone know the book I'm talking about perchance?