Here are some resources for WordPress security:
Learn how to use WordPress, the most popular website building software, at Portland Community College. PCC will offer the WordPress course, "Take Control of Your Website with WordPress" starting on April 9th and again on May 14th.
WordPress.com is a communal version of WordPress that has limited functionality. WordPress.org is the site behind the software that is free for anyone to use.
If you have an account with WordPress.com, I highly recommend moving your site to your own installation of WordPress. The good news is that most website hosts offer one-click installation of WordPress (Which comes originally from WordPress.org.)