Migrate a Source Safe database to SubVersion with history

I'm considering the migration too and I have found some pages that may help you in the process:

• Moving from Visual SourceSafe to Subversion
• Vss2Svn Project page
• Migrating from SourceSafe to Subversion

This 3 pages provide information on methods to migrate the complete history from VSS to SVN

You can try VssMigrate. It is a C# port of PowerAdmin's VssMigrate which has the capability to "Resolve the individual VSS-checkins to atomic SVN commits via the approximate timestamp".