Finally, a good Visual Studio add-in for subversion, VisualSVN.  I just found out about this plugin yesterday and so far have been using it without any problems or issues. It integrates with Visual Studio and uses TortoiseSVN to perform its actions. It also creates a new menu to access all of the Tortoise functions.  When you invoke any of the actions it creates a new Tortoise screen as a modal window over Visual Studio.  Here is a quick screenshot:

You can use the fully functional demo version free for 30 days.  After that, you can register it for a measly $19.  It's well worth the money in my opionion. I highly recommend this plugin for anyone doing .NET development with subversion as your source control repository.