CSS Frameworks are extremely helpful and time-saving. When you are making a website, do you really want to spend a bunch of time figuring out positions and making print stylesheets? CSS Frameworks save you time on everything from resetting styles to common things that Internet Explorer break again and again.
3. YUI Grids CSS
4. 960 Grid System
7. jQuery UI CSS Framework
12. Unobtrusive CSS
Hopefully these will save you time and frustration!