Looking for a way to integrate Subversion with Visual Studio .NET 2005 I came across AnkhSVN - an open source VS.NET plugin which does exactly that.
My current tests show that the tool works pretty well and in its latest generations is very convenient. It supports not only Visual Studio 2005, but 2008 and 2010. Make sure you install the latest version. I also suggest that you use WinMerge instead of its built-in diff viewer. You can do that by selecting "Options" from the "Tools" menu in Visual Studio and then going into "Source Control" subtree and selecting WinMerge as the diff viewer in the "Subversion tools" section.