http://cloford.com/resources/colours/500col.htm
http://css.maxdesign.com.au/selectutorial/ Select Tutorial
http://www.brainjar.com/css/using/ Overview of CSS Style Sheets; including review of selectors
http://www.barelyfitz.com/screencast/html-training/css/positioning/ Tutorial on positioning
http://www.brainjar.com/css/positioning/ CSS positioning summary
http://www.dynamicdrive.com/style/layouts/category/C13/ Liquid layouts [note: these pages mix 'liquid/fluid' layouts which are %-based and 'elastic' layouts which are em-based]
http://css.maxdesign.com.au/floatutorial/ Float Tutorial
http://www.alistapart.com/articles/negativemargins/ Float using negative margins
http://www.smashingmagazine.com/2007/05/01/css-float- theory-things-you-should-know/ Floats
http://www.quirksmode .org/css/clearing.html Floats and clearing
http: //www.complexspiral.com/publications/containing-floatsContaining floats
http://phoenity.com/tests/custom_corners_two.html Example of rounded corners boxes
http://www.quirksmode.org/css/overflow.html Overflow, hidden
http://www.d.umn.edu/itss/support/Training/Online/csstips/overflow.html Image overflow
http://www.smashingmagazine.com/2007/05/10/70-expert-ideas-for-better-css-coding/ Workflow and good practices
http://www.htmldog.com/examples/ List of properties for HTML and CSS; look at LAYOUT examples. Also see IMAGE REPLACEMENT
http://www.glish.com/css/3.asp 3-column layouts
http://blog.html.it/layoutgala/ Layout Gala
http://blog.html.it/layoutgala/LayoutGala07.html 3-column layouts
http://blog.html.it/layoutgala/LayoutGala33.html 2-column layouts
Xray tool for CSS analysis: http://www.westciv.com/xray/xray_more.html