how to attach these legs to body?
 

all made by nurbs

Mike, ( MtMckinley) has a tutorial on his sight, or..used to atleast, on how to attach nurbs arms and legs...
heres his link
http://www.mtmckinley.net

download the free cartoon dog tutorial and it will give a demonstration on converting nurbs to polys then attacthing... hope that helps.... it is somewhere in the 2nd or third tutorial i beliveve.

that hip set up is really less than ideal. You really want a hip area with hole for each leg to connect to.

Ok, lets build that hip... select the bottom ring isoparm of the top cylinder (torso). From the edit curves, select duplicate surface curve and move the newly created curve down. Now you need to create a surface from this curve. If it is planar then cap it with planar. If it isn't planar, switch to edit point mode and select four edit points on the curve (at the axis poles preferrably). With these four edit points select, select detach curves from the edit curves menu. You should now have four separate curves. With the 4 new curves select, select surfaces->boundary. Now select the top ring isoparms of each leg and project onto the boundary surface. trim the project rings out of the boundary surface
fillet from the surface to the torso, and from each leg hole the corresponding leg... whew. Now you should be able to attache the hip to the body and the legs to the hips.

oh yeah, you can rebuild the new surfaces ensure a correct number of spans in UV to facilitate a clean attach operation, and delete no longer needed curves that were used to build the surfaces.