JuicyBomb has a nice tutorial on how to make poses for Second Life avatars with DAZ Studio.
Avimote PoseMaker PE is a HUD for sale at the Second Life Marketplace which allows you to move and pose your avatar in just about any way you can imagine. Align perfectly, bend your avatar only the amount that looks good, position your arms to accommodate the skirt you happen to be wearing and just about anything else you can think of. This HUD is very convenient for photographers. Available at the Second Life Marketplace for L$2450.
This video tutorial by Three Guides in Byzantium explains how to use Poser 7 to make poses for Second Life and OpenSim.