Free alternative that is worth a try (especially when Poser 6 chokes on a complex scene):

1. Pose scene in Poser 6 as normal but don't get exotic with material shaders
2. Export whole scene to wavefront obj
3. Save PZ3 too
4. Import PZ3 and obj (and partner mtl file) into PoseRay
5. Use Poser OR PoseRay native lights (camera comes from PZ3)
6. Fix any busted materials (shader materials not supported but maps, bumps and transparencies work)
7. Watch for opportunities to use nice POV materials (e.g. for metal objects and glass)
8. Launch POV-Ray renderer from PoseRay

Pros: Fast, High Quality render, Solution for when P6 fails.
Cons: Only has simple material handling, Might need to weld/smooth organic objects so that material zones flow into each other nicely (quite simple to do this), Radiosity seems a bit troublesome and quite slow.

PoseRay from
http://mysite.verizon.net/sfg0000/

POV-Ray from
http://www.povray.org/

Most of the 4 and above character scenes in my gallery are using this rendering approach.

HTH,
Jovial.