i have heard of animations being designed in poser and exported to second life.
but all the objects here are pretty hi resolution, and second life is pretty low res.  what you could do is get uvmapper and open some of the textures here and open some of the second life textures and see if you can stretch or push them to fit. 

i believe also that second life may have a texture size limit that you might have to abide by and of course beware of copyright issues.  you definitely want the texures as small as possible since every zone in second life loads every single texure (super laggy that way)

as for using objects (people, clothes whatever, the mesh) from poser, it seems very unlikely to me that they will be useable in second life...(unless you were to limit them to an empty zone...)

some of the animations in second life are pretty &^%$ good too...