The GPWA uses vBulliten and has customized it to the needs of the organization. As far as what software folks use, the list is endless. There are many options from coding your website, using an editor program like Dreamweaver, Content Management Systems (CMS)... Joomla, Wordpress, Drupal, Mambo, Nuke.... it really is endless.
Many newcomers start out with Wordpress as it is one of the easiest cms programs to learn. A lot is a matter of personal preference too. Like raphinx said, you could get involved in a webmaster forum that focuses on design and programs to build websites.
Have a long look around here and you will find a ton of information on what folks use.
Good luck in your new venture!
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"People who are unable to motivate themselves must be content with mediocrity." ~Andrew Carnegie~