Here are some excellent articles on database design & normalisation - most are written with Access in mind, but 99% of the principles and techniques apply to every database under the sun, so they are well worth a read no matter which DB you use!
Understanding Relational Database Design
How the Table Analyzer Wizard Works
Database Normalization Basics
GeekGirls.com Database Tutorials
Some tip-style pages:
Database Design and Modeling Fundamentals
Does anyone else know of any quality articles/resources on these topics? Also, could one of the moderators could mark this thread "Important"? Cheers!
EDIT: Added tips pages
EDIT: Removed the mailing list links, which are now sadly deceased.
Concepts of Database Design and Management