PoserPro (the original Poser 4 Pro that is) and onwards reads them. Not sure about Vanilla Poser 4.

No need to decompress unless you want to poke around inside the file. Poser reads them just fine :) 

FREEBIES! | My Gallery | My Store | My FB | Tumblr |
You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.