Check out this thread...

http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3975733&ebot_calc_page#message_3975733

AmbientShade was kind enough to provide a nice walkthrough of exporting via the GoZ option form the Poser figure menu, and setting the mesh up to work on in ZBrush...

...in brief, once in ZBrush drag onto the document... hit T, to go into edit mode.

then F to frame... drag outside of mesh to position it (shift key and drag to snap to a plane or however you'd describe it) then maybe F to frame it again.

Then use the Scale and Move options maybe to zoom in on it... etc.

Does take a bit of getting used to... but it comes to you, I've found.