Karl,
The PHP guide is the best one we have. It's pretty transferable.
The core .NET C# you'd need would be something like this.
var client = new WebService.MobileDevice();
client.AllowAutoRedirect = false;
client.UserAgent = "UserAgent";
You'll need to add the MobileDevice.asmx web service from the sample project to your client solution as a web reference. If you're not familiar with web services in .NET then I'd suggest reading the intro guides on MSDN.
I hope this helps. If you'd like to publish your solution as a blog post please let me know.
Thanks,
James