Each skeleton has a Pose Library that stores poses for that skeleton. The Pose Library is saved with the skeleton.

The Poses panel is in the Tools section. The poses panel is a tear-off panel.

Click Add to add the current pose to the list.

Click Del to remove the selected pose.

Double-click a pose, or click Use, to set the skeleton to the selected pose.

Poses can be renamed. Renaming works just like it does in Windows explorer: select an pose, wait a moment, then click it again to enable editing (or, simply press F2).

The Pose panel also holds the Blender: a tool for mixing poses.