Large e-commerce sites
can be built with CSS - it is just quite difficult to do.
For the two sites you've shown - the developer should be shot lol. Tables as a means of layout are inaccessible, obsolete, overweight and rubbish.
What you say about being taught table based development I can believe and empathise with, but that was then and times they are a changin'. CSS and (tableless) xHTML are the norm now.
As far as learning CSS, it's very simple to get the basics. Try these:
CSS For Webdesigners - 613 helpful links for webdesigners
Web Developer's Handbook | CSS, Web Development, Color Tools, SEO, Usability etc.
Good luck, and remember - if you need help, that's what we're here for :)