Follow the following steps:
1. Get your domain name. GoDaddy.com is my first choice. Do you have specific domain name that you want to have by paying extra money? Then, try at Sedo.com. 3 char domains usually cost $4000 to million depending on the combination of characters.
2. Web hosting company. Do you know the possible size of your website content? If it is less than 100 MB in first year, then go for www.1and1.com with base line webhosting plan. Get MySQL database. It might cost you $30 in first year.
3. What kind of content do you want to put? Blog, informative or wikipedia model.
If it is pure blog, then Go to WordPress.org and download the WordPress Blogging software. Free of charge. For single domain, 1and1.com simply offers you this blogging software, and you don't have to install it. They have installed it, you just have to activate the blog. If you download WordPress to host multiple domains, then use FileZilla software to upload your files. It is an excellent FreeWare.
If you want much wider content on your website, then go for either Joomla or Drupal CMS. I love Drupal over Joomla because it is easier to handle by one man. It is more efficient and easily scalable. It was number 1 CMS software lastyear. Joomla lost for the first time or so. You can host multiple websites / domain names under Drupal CMS using FileZilla as your file upload download / ftp software. You should have MySQL database. e.g. www.GeoTech.net
If you want wikipedia model, then go for Tiki-wiki. It is really the best one probably lead Drupal and any other freeware CMS in coming years. It is too big, but worth if you are beginning a new project. I have just started it: http://www.Pokhara.org/ and http://www.GeotechOnline.com/ as a trial.
You can find other CMS as well.