if anyone is looking for a very good open source CMS it means they are looking for e107. It can be found at www.e107.org You can very easily customize everything in it, and it has a great community of people ready to help you out in any problem you may encounter with it. There are also a great number of themes, styles and plugins for it. I am using right now and if i will ever get an account of free web hosting here you can see exactly how a site made with it looks like. All you need is the content for your website, the rest is done by e107.
Cheers all and i hope you like it. It is great for someone with very little programming experience in PHP
Cheer mambo cms
i agree raver, e107 i a very good CMS, and i use it on most of my sites, i think mambo is tacky, i spent most of my half temr movin one of my site off mambo i hated it that much