AFAIK, the method described in the Introduction to Rigging BSoD, http://wiki.blender.org/index.php/BSoD/Introduction_to_Rigging/The_Armature_Object
1.2.2 Resizing a Bone sub-section
doesn’t work anymore in version 2.45 (or earlier?): if both ends of a bone are selected Shift+S > Cursor to Selection sends the cursor to the root point, not in between both ends.
If I am right I’ll try to get this section edited but please correct me if I am wrong.