Where I've Been embeds your whereivebeen.com maps on your WordPress blog.
You may use multiple maps by using multiple shortcodes with different user id's.
I have personally only tested the plugin on WordPress 2.7+ installations. The plugin makes use of the Shortcode API that was released in WordPress 2.5, so it will possibly work on all versions after 2.5. If your feeling brave, test it out and let me know.