To some extent it depends on your coding techniques.
What is clear is that all sides regarding the GUI
would have to be re-written.
But if you have a solid well written generic Business Logic
layer in pure code it can probably be used with minor configuration.
If you haven't decoupled your BL and GUI, at least you know now why one should :)
You mentioned you tried asp
. Is that classic
? note that ASP.NET as exactly what you mentioned, drag-n-drop controls to a form GUI with the Visual Studio IDE etc, very easy (and while we're at it, you can consider other technologies, like flash, silverlight, mvc)
As for your wish for avoiding IIS
, it seems to me the simple solution for hosting a web app, it does all the work for you, simple as that.
Without IIS you'll have to manage the connections with the clients and the HTTP module etc, quite a hack.
But if you have other solutions you are more acquainted with that's fine.