Take a look at Chapter 5 of Version Control with Subversion.
To move a repository from one server to another you will want to use the
svnadmin dump and
svnadmin load commands.
Subversion provides such functionality
by way of repository dump streams. A
repository dump stream (often referred
to as a “dump file” when stored as a
file on disk) is a portable, flat file
format that describes the various
revisions in your repository—what was
changed, by whom, when, and so on.
This dump stream is the primary
mechanism used to marshal versioned
history—in whole or in part, with or
repositories. And Subversion provides
the tools necessary for creating and
loading these dump streams: the
svnadmin dump and svnadmin load
The usage of svn dump is
svnadmin dump reponame > dumpfile
and the usage of svn load is
svnadmin load reponame < dumpfile.
The help page for VisualSVN that references the usage of
svnadmin dump can be found here and
svnadmin load here.