Here are a few resources I found very helpful in dealing with all of the cross-browser inconsistencies in CSS implementations. Note: these will not teach you CSS—there are places for that—rather, they teach you how to wrangle it into submission and produce mostly-consistent results.

The Noodle Incident's Box Lessons - an indispensable font of thorough information on layout box positioning problems and workarounds. The core layout of this page is now based on a layout researched and coded by The Noodle Incident.

There's also more information on hacking boxes at glish.com and tantek.com.

I'm still working on font size keywords, but that's another area that takes some hacking to implement elegantly.

There's a good article on migrating from table-based layouts to CSS on A List Apart. One thing I plan to get around to doing is implementing the Browser Upgrade Campaign discussed in that article.

Most of the readers here have at least CSS1 support or better, but there are some who don't. An elegant, gentle-but-not-required suggestion to upgrade would be a nice feature and help push the Web toward an age in which these standards actually work consistently.

If there's anything else you need to know, The Web Standards Project has linked to many excellent resources.

Take the plunge! It's quite an education!