First off, read the book: http://svnbook.red-bean.com/
Second, here's how you do it really quick.
Right click where you want the repository dir to go and click "Create Repository"
Get your project together and clean it (remove all unnecessary binaries)
Right click the project dir and click "Import..." - then choose the repository dir you just made. Once it's imported (if there's no file locks, so close VS or whatever first) then you browse the repository to see if it ended up where you want it.
Ok, it's still not under real subversion control, so the final step is to check the project out to another project directory. I usually end up with something like <ProjectName>SVN - this is the working local copy.
Delete your old project, or move it if you're feeling paranoid, and always work off your local working copy. I recommend deletion to avoid confusion with directories. When you're done for the day, or done a feature, whichever you prefer, right click the directory and click "commit" - all of the changed files will show up. This includes the binaries - I recommend you do not put the binaries (except art) under SVN control. Deselect the binaries and proceed. Voila, revision control.
Hope this helps.