I have been trying to configure the blog module in my skin for a while now, but it just lists all of the contents down the page and won't display them in columns. Here is a screenshot of what my blog looks like now:

I have seen it configured on other DNN sites where there are 3 columns and the posts run down the middle while the search, calendar, categories, etc are all on the sides. Can anybody help me figure out how to configure the blog module with CSS?

When you install the blog module onto a pgae you should get 5 actual modules as helpfully noted at:
http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/92/threadid/6068/scope/posts/Default.aspx
(They are unfortunately not easy to understand on their own.)

Then each of these 5 modules can be moved around into various "panes" on your DNN page. So I think you need to ensure your page skin you are using has two or more columns to receive the modules. If so, when you click on the modules' action/context menu, you should see entries like "Help", "Print", Settings", and most critically for you "Move". Selecting "Move" should show: "Move Up", "Move Down", "Move Bottom", and [providing you have a skin that allows it] "Move to Right Pane", "Move to Center Pane", etc. If you don't see something like these last two entries, then look at adding a new MULTI-COLUMN page skin to your site and using them for your blog pages.