Let me say first (again, actually) that I’m totally clueless when it comes to web programming: I’ve been working on desktop applications (and one device driver) for the last few years. Now our client is considering moving our application to the web, and never having done this I’m not sure what the best approach is.

From what I understand,.net is that it supposed to be good for this kind of thing. I haven’t gotten to deep into it, but it seems to offer a great deal of power using languages similar to what I already know. The only drawback is that you have to use Windows servers, and I’m not sure if this would be a good thing being that over 15,000 users currently use the desktop version of this application; we expect about 80% of these would log in and use a web-based version in single four-hour timeframe.

We have other web stuff using Sun servers and Portal (which I know nothing about), and this seems to be the preferred method of handling large numbers of users. Sun, as I understand it, makes better servers than M$, but I know very little about Portal or PHP and would have (I believe) a steeper learning curve porting this application over to using them, not to mention everyone here seems to despise working with Portal.

One other factor is that whatever solution I choose, the data will be stored in an Oracle database.

My questions are:
1. How closely can I make a web version look to my desktop version with .net (assuming that it is a straight-forward windows app)?
2. Can a Windows server (or servers) handle the number of users we are talking about (without astronomical expense)?
3. How closely can I make a web version look to my desktop version using Portal and PHP?

I know this isn’t my first post on the topic, but any help would be greatly appreciated. Our client just came up with a big wad of cash and I need to devise a plane to help him spend it.