Hi guys
I'm new here. I had been reading a long time here on the forums but now I registered finally.
And got a question for you.

Since yesterday I've got successfully installed a X11-connection from my WinXP to a RedHat EL 5 - Box. Now there's a web portal needed.

So I have to make a homepage where are a few icons on it. If you click on one of those icons, there should appear a window with a X11-environment (like xming, cygnus).
Is there any possibility to do that? I've got absolutely no idea how to make this run... :/

Hope you can help me...

Best Regards, Mario

This doesn't directly address your need, but VNC offers a web interface to configured desktops.

RealVNC - Java VNC Viewer

I would guess that you will want a bit of cgi or php code on your webserver.
It will need to read the address of the requester (that info is readily available to both cgi and php scripts as a predefined variable).
You can then either do some clever port probing to find which display number, or ask for that on a web form, or just assume display number 0.
Once you have those, you can determine which X11 display to send the X11 application to (eg yourwebsurfingcompter.address.domain:0). You'd then either need to authorise the webserver on your web browsing computer or have it allow any X11 connections (quite dangerous). Another option would be to have the user supply their X11 MIT cookie via a web form but that feels like overkill.

Once you have these bits of information, it's just a matter of having your cgi or php run a local application (as the webserver user most likely) with the display (usually either the DISPLAY environment variable or the -display parameter) set to be the display of your web browsing client (determined near the start). Remember to background the application so your script doesn't hang.