I recently moved my development server from a linux box to my primary machine, an iMac. I wanted to move my subversion repository while maintaining the file histories for everything inside. Worrying that it was going to be a huge issue, I was happy to discover it was completely simple:

On the existing repository machine, run:

svnadmin dump /path/to/repository > repository-name.dmp

Transfer your dump file to the new machine and then, create a repository. Once subversion is running and you have your repository created, import the dump file:

svnadmin load /path/to/repository-name< /path/to/repository-name.dmp

You're done!