Hi,
Welcome to Visual WebGui...
In order to start working with VWG you need a Visual Studio 2005/2003 with the ability to develop ASP.NET. Visual WebGui extends ASP.NET so all the prerequisites for ASP.NET apply to VWG as well.
The installation is pretty strait forward and installs the Visual WebGui runtime and design time assemblies. In order to deploy your project you do not need to install any thing on the server. That is made possible because you should deploy with your VWG application the VWG runtime which is the Gizmox.WebGUI.Forms.dll, Gizmox.WebGUI.Common.dll. and Gizmox.WebGUI.Server.dll.
You should take a look on the different quick start videos here and the documentation here.
Hope that helps,
Guy