Take a look at server configuration in the SVN Red Book.
You have three choices - using svnserve, using svnserve over SSH, or Apache HTTP. Each has pros/cons, and these are discussed. Note also that you'll need to configure your firewall (port-forwarding etc.) as required.
From the Red Book article:
If you're trying to set up the simplest possible server for your group, a vanilla svnserve installation is the easiest, fastest route. Note, however, that your repository data will be transmitted in the clear over the network. If your deployment is entirely within your company's LAN or VPN, this isn't an issue. If the repository is exposed to the wide-open Internet, you might want to make sure that either the repository's contents aren't sensitive (e.g., it contains only open source code), or that you go the extra mile in configuring SASL to encrypt network communications.
(my emphasis)