So CodePlex launched support for TortoiseSVN, more details about it are here. In the past there have been a couple of HealthVault projects which chose to do something else since SVN was not available on CodePlex, so this is a really great news. The SVN support is through SVN Bridge - essentially CodePlex is now hosting a bridge server which will let you talk to the native TFS project using a SVN client. Well - may be you can check out the HealthVaultD2C sample using TortoiseSVN now :).