I'm using NI's Labwindows CVI and I'm trying to integrate source control. Supposedly it plays well with anything that fits the MS API (MSSCC/SCC) but I haven't found this to be the case in practice. I'd love if there was a SVN service that works well with it, but I suppose that's asking for too much.
The way that you should set up your development should be as follows:
Option 1:
Do your normal development in LabWindows CVI.
For source control, use Subversion, and for your interface to Subversion, use TortiseSVN. I have been using TortiseSVN with VS2008 and VS2005 for a while now, and I find that it is just fine.
Option 2: Do your normal development in VS2005 or VS2008 and link to the Measurement Studio libraries supplied by National Instruments. There, you will have the option of using C#, C++, C, or whatever your heart desires. You can also integrate other libraries or subsystems, such as MatLab, and you would get the added benefit of framing your questions in terms of Microsoft Technologies vs National Instruments technologies, where the support is much smaller.
You can integrate Subversion with Visual Studio through a number of addons (http://ankhsvn.open.collab.net/), but again, I prefer to use TortiseSVN.
Option 2 is nice because you are able to use the best of all worlds, Visual Studio >> LabWindows, Measurement Studio >> roll your own, TortiseSVN >> VSS.