The arachnid figure was created by Codeman3D, and was purchased from bbay.com. The spider in this figure is slightly modified from the original. The web geometry would be a massive number of polygons, so the web in these images is actually a series of 2D planes with partially transparent texture maps. The image was rendered in Bryce 4.
The skeleton is from Zygote, while the icy skin is a standard Poser figure with transparent texturing applied. The riddle box and web strand supporting it were modelled in Cinema 4D XL. The scene was rendered in Bryce 4.