Acme How To.com
Provides articles and information to help you understand, diagnose, and repair the things you use.

Do It Yourself.com
Find information about auto maintenance and repairs, gardening, home improvement, home repairs, etc.

eHow.com
Claims to offer "clear instruction on how to do (just about) everything."

How Products Are Made
Detailed descriptions of the manufacturing process for a wide variety of products from baking soda to heavy machinery.

HowStuffWorks.com
From cars to spacecraft, this site describes how things work.

How to Clean Anything.com
Contains more than 1,000 tips from a "group of cleaning professionals" for cleaning your house, yard, vehicles, pets and belongings. Also features stain removal ideas, a glossary of cleaning terms, a directory of cleaning service providers, and feature articles.

Knowledge Hound
Large directory of how-to information.

Repair Clinic.com
Includes free repair help and information about appliance parts.

SoYouWanna.com
Teaches you how to do all the things nobody taught you in school.