Thanks to issue 203 of .NET magazine for providing a very informative article on CSS frameworks. I have started using the BluePrint CSS framework, it is very easy to get started with and has some useful features to get CSS up and running extremely quickly.
Check out their website to download the code and start using it.
They also have a sample page here, showing what is possible.
Very helpful tutorial from Alex Griffioen, on how to create buttons in CSS.