Help - 3 Column Templates?

Existence is Wonderful very badly needs a template update (and just a general aesthetic/structural overhaul).

In particular I want to go to a 3-column layout, with the main post text in the middle and two sidebars (which will contain archive and profile links, various lists, etc.) on either side.

There are a number of example 3-column Blogger templates around the Web I've found, some of which are kind of cool and might work okay provided I could customize them a bit. But so far, all the examples I've tried have given me errors when I've posted the code into the HTML field. Blogger has a few templates to choose from, and there's some limited WYSIWYG customizability for these, but it's a bit too limited for my taste, in particular in that none of the standard templates have 3 columns.

I know that part of the problem here is my own limited knowledge as far as Web authorship tools go. I used to be decent at HTML back in the Web 1.0 days, but now with all this new CSS and Java and XML and other miscellaneous featureage being part and parcel of making one's website look nice and behave well, I'm afraid I'm woefully behind the curve, much to my geekish embarrassment.

In any case, I would very much like to remedy my ignorance, but I haven't had much luck finding good tutorials on using 3 column layouts in blogger. I've googled a lot already and I know it's easy to find example templates and supposedly downloadable freebies (which can then be customized), but all the tutorials I've come across seem to either (a) suggest things that don't seem to work when I try them, and/or (b) go way over my head.

So if anyone reading this can point me toward any -- preferably ones you've actually personally used and confirmed to work -- I would be most grateful.

(Also, right now I am not planning on switching to Wordpress or Typepad or any other service, so I am not looking for suggestions to that effect, I am specifically looking for help doing what I want to do in blogger.

Maybe at some point I'll switch services, but I don't want to deal with moving domains and all that right now and worrying about my posts actually getting transferred over properly, I just want to update the appearance and make the blog a bit more navigation-friendly overall.)

Thanks in advance!