Rigging a straight tube of polygons so that it can be bent like you describe is a very good introduction to rigging, although it's a bit tedious if you go with a lot of bones.  Once you figure out how to get one particular bone to bend the way you want it to, which isn't too hard, then you just repeat until you hit the end of the line.  I don't really recommend making it dynamic because you don't have any control over what the cord will do without A LOT of trial and error, although with luck it can give you some pretty nice results.  Setting up a single dial, or a set of dials, to bend groups of bones together and make a nice curve is actually the easy part of the job, it can be done with a CR2 editor or as others are suggesting you can use some utility like EasyPose or Poser 8+'s Dependent Parameter feature.

Start with something very simple to get a grip on how bones work - just make a plain old cylinder, with two polygon groups defined, "base" and "cord1".  Import it into Poser, go to the Setup room, and draw two bones, one for each polygon group (base and cord1).  This is best done from one of the non-orthographic cameras (top or side cameras).  Make sure that the Internal Name of each bone matches the polygon group names base and cord1. When you exit the setup room, you shouldn't get any warning message about "polygons that do not belong to a bone"- if you do, then something is probably wrong with your group names and the rig won't work.  Stop and make sure your groups are properly included in the OBJ, or at worst define them with Poser's built-in group editor; if you can get this done in your modeler I strongly recommend you do it there, because Poser's group editor is awful for this purpose.

When you get past that point with no warnings, save the new figure to the Figures library and create a new scene, load your figure, hit Ctrl+Shift+J (Joint Editor) and start fussing with joint parameters :)
http://www.tubechunk.com/video/q8jxSOL_MAM/Rigging-Figures-for-Poser-part-1-of-3-by-PhilC.html

http://www.tubechunk.com/video/PfcPu83gZNs/Poser-Joint-Parameters-part-1-of-2.html

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