My free host should be up and running within a week or so, but I was wondering:

How can I allow people to host their domains on my server (we are running our own server)

Is there something we need to install, or is there a free service somewhere that will let us do this?

Cheers.

what control panel are you using?

zPanel

you can lease cPanel for $20 a month, thats probably the best thing you can use to run a hosting company