I downloaded Haml from here: http://rubyforge.org/frs/?group_id=2760. When I extract the zip there are a bunch of .rb files and the official web page talks about gems. I think this is some Ruby stuff.
Can I learn Haml and Sass even if I don't know Ruby?
If I have to, how do I install all this on Windows XP?
Implementations
The official implementation of Haml has been built for Ruby with plugins for Ruby on Rails and Merb, but the Ruby implementation also functions independently.
There are also implementations in other languages:
* GHRML (Python) * LuaHaml (Lua) * MonoRail NHaml (ASP.NET) * NHaml (.NET) * Fammel (PHP) * pHAML (PHP) * phpHaml (PHP5) * haml-js (JavaScript) * Text::Haml (Perl)
Do you know any of those languages?
I don't think you need to know ruby as such since both projects are domain specific languages for writing html and css. I think knowing a bit of Ruby will help you in using both projects since you can leverage Ruby's capabilities in abstracting common things away in your code.
Regardless of whether you want to learn Ruby or not, you will have to install Ruby and the dependencies for Haml and Sass in order to be able to use them on Windows.
Finally, Ruby Gems is a package manager for Ruby, that is used to install and manage Ruby libraries on your system.
Actually, if you don't want to install Haml/Sass at all but want to try it out, you might want to play with: