Carbon Factory Development - Crawls your site and provides a list of potential keywords. - http://www.carbonfactory.com/meta_generator/
Web Displays - Free HTML Meta Tag Generator - Generates tags for copy and paste, based on basic and optional data supplied. "Long version" of the form includes an explanation for each field. - http://www.webdisplays.com/guide-web-design-tips-tutorial-help/quick-meta-tag-generator.html
Dr. Clue Meta Tag Builder - Generates Meta tags based on information you input into the form. - http://www.drclue.net/F1.cgi/HTML/META/META.html?PAGE_NO=7