I've done a LOT of this. But I use Visual Studio and either the stock WebBrowser control, or some other web browser control.
That gives you the most power quickly. Other than that, you need to start doing the networking yourself.
It's not very hard, and you can do quite a lot very easily. However, you need to know C# or VB.NET or some other CLI/CLS language, e.g. F#, IronPython, IronRuby, etc.
This is REALLY old:http://renegademinds...abid/82/Default.aspx
But shows some basics for submitting a form in VB.NET. You can probably find more stuff at the Code Project.