Hello,
I posted this last week, and it dawned on me that some might come into the forum here looking for help with this. I was working last week on a project where I wanted to move the sidebar for Twenty Ten to the left side with Custom CSS, and I've posted the relevant changes here: http://ryanmarkel.com/2010/07/22/flipping-the-sidebar-in-twenty-ten-with-custom-css/
Keep up the good work helping each other with CSS changes! This is a great resource for WordPress.com users.
If you want to skip the article, here's the code:
/* LAYOUT: Two columns-reversed
DESCRIPTION: Two-column fixed layout with one sidebar LEFT of content */
#container {
float:right;
width:100%;
margin:0 0 0 -240px;
padding:1em 0;
}
#content {
margin:0 20px 0 280px;
}
#primary,#secondary {
float:left;
overflow:hidden;
width:220px;
}