Teach Yourself MySQL in 14 days, Perkins & Morgan @ Sams (Excellent starter, believe it or not)
MySQL Bible, Suehring @ Wiley
Pro MySQL, Knuckenberg & Pipes @ Apress
MySQL Stored Procedures Programming, Harrison & Feurenstein @ O'Reilly
http://www.php.net/manual/en/ref.mysql.phpTeach Yourself PHP in 24 hours (3rd Ed) Zandstra @ Sams
PHP Cookbook, Sklar @ O'Reilly
Object Oriented PHP, Lavin @ No Starch
This is a really small list of the books that I own and have been through. I have many more, but these stick out as great starting points. The 14 days and 24 hours books are great because if you're like me, you can do them in a day or 2 and get a really fast immersion into the languages and tools.
As an old dBase III and Clipper guy I can relate and probably answer any of your structural or conversion type questions. You've made the right choice, believe me.
Biggest difference: dBase (and Clipper therefore of course) a "database" was actually a table. Silly of them.
Good luck!
/p