Start by following Brians instructions on getting started with Subclipse.
Before checking out your first working copy, you’ll need to create some folders and import the files for your repository. Start by connecting to your repository (e.g. http://svn.riaforge.org/lightwire). Then right click on the repository, new, new remote folder and create folders for branches, tags and trunk. Under trunk, create a folder with the name of your project.
Once you’ve done that, right click on the project named folder in subclipse (for me it was trunk/lightwire) and select import. Select the folder on your hard drive to import from which contains all of the files for the project and click “finish” and you’re done.
You can now go on to check out a working copy as in Brians instructions. If you have any questions, there is a good online book and Simeon always has a bunch of great Subversion postings that are worth checking out. Just search his blog for Subversion.