By "won't install" what do you mean? Does it error? Etc.
I have installed it successfully on my home server. Tutorial here: http://www.howtoforge.com/perfect-server-ubuntu-9.04-ispconfig-3
I managed to get it working once on a virtual machine. But I didn't find it very helpful or easy to use so I gave up and used WebMin instead.
Well, half of the packages it requires apparently doesn't exist or something. I'll be trying to get it installed soon again however, I doubt it will.
I'll try that tutorial sometime, thanks!
I've used Webmin before, for some reason I just don't like it. The interface needs some work, other than that, it functions well.
I like webmin, other than the fact it doesn't support monitoring lighttpd by default.