I want to migrate my VSS(Visual Source Safe) to Subversion (SVN), after some search, I found two tools,
VssMigrate, A tool, written in C#, for importing a Visual SourceSafe database into Subversion (SVN) while maintaining the complete file history.
vss2svn is a Perl script (vss2svn.pl) and accompanying C program (ssphys.exe) to migrate revision history from a Microsoft Visual SourceSafe (VSS) database to a Subversion repository.
I have not test which one is better, but I am familiar with C#, I like try the first one.
Winform Version VssMigrate,
http://files.cnblogs.com/mine/VssMigrateForm.rar,
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