You are never going to be able to make a "virtual reality" with poser, you might be able to script together some rendered videos, but it wont be anything truly interactive....

In fact you will never find a "virtual world" that works in realtime with poser quality comparable visuals (well unless you can fund a air craft hanger sized render farm :D)

If you want an interactive virtual world your best bet would be PC gaming, there are plenty of "sandbox" games and MMO's that offer 3D worlds... and if you mix that with Nvidia's 3D setup (you will need nvidias 3D box and glasses, nvidia GFX card and a 3D compatible monitor) you will get a really nice experiance !