There are several options. We're all about the options.
... from our Sourceforge Project Site. The latest version is always here. Then you should read the installation instructions.
... if you can handle the twiddly bits, you can check out the latest version from our SVN repository, either from the Trunk (not guaranteed to be stable) or one of our Release tags. Point your favorite Subversion client at:
http://www.turtolcms.org/svn/Trunk
... Coming soon, TurtolHosting will be available to host a TurtolCMS site for you.