I was relucatant to mention this at first, but you might find a couple of my articles helpful in getting started.
I wrote one recently for Red Hat Magazine called "Getting Started with MySQL":
http://www.redhat.com/magazine/007may05/features/mysql/ It explains the very basics of using MySQL.
For learning how to interface PHP to MySQL, I wrote an article for SysAdmin Magazine last year that might help you to get started. However, this is a print magazine, so you'll have to read it on my web site:
http://russell.dyerhouse.com/cgi-bin/article.cgi?rec_id=80
For importing data from Access into MySQL, I wrote an article on the subject back in 2003 for Unix Review. If I wrote it today, I'd probably do it differently, but the concepts and details are still pretty accurate:
http://www.unixreview.com/documents/s=8472/ur0307c/
These three should help you to get started over the weekend without having to put a lot of time in researching or having to spend a bunch of money on books yet.
Russell Dyer
Author of "MySQL in a Nutshell" (O'Reilly 2005).