It's simple. Just go to these links to use free products and learn how to build virtual reality chat sites:

You need vrmlpad (it allows you to see a vrml source):
http://www.parallelgraphics.com/products/vrmlpad/

Internet Space Builder (to build buildings):
http://www.parallelgraphics.com/products/isb/

and a great tutorial site:
http://www4.tpg.com.au/users/gperrett/contact.htm

You do need a PC. The best browser to see virtual reality is blaxxun. You can get a download link at http://www.blaxxun.com/download/contact/contact5/blaxxunContact51.exe

Like I've advertised before, to see a sample of my thesis' virtual reality Roman forum, just go to http://magellannarfe.com . It's huge, so I understand if you don't want to see it and wait for the download. It's meant for academia since I use it to teach classes about Roman architecture.