Conclusion
If you've completed this tutorial, and the HTML tutorial, you now have the basic tools at your disposal to create modern, standards-compliant websites, using HTML to structure the content of your pages and CSS to apply presentation.
CSS can be quite difficult to get the hang of at first, particularly when using it to create page layouts, but the time taken to learn it will guarantee savings in the long term, as it offers so much more flexibility than presentational HTML and table-based layouts, and also has many benefits regarding accessibility and maintenance.
There are many websites containing lots and lots of useful resources on CSS, including design showcases, tutorials, tips and tricks, and guides to fixing browser bugs. You can find a few on the links page of this site, but a bit of exploratory googling will turn up many, many more. Enjoy!