Bones affecting mirrowed image

Can you creat bones that effect a mirrowed image? or beter yet make mirrowed bones, posibly on the .l and .r extensions, so to animat walking?

thank in advance

Yes, you can already do that.

For 2.40:
(This tutorial shows how you can create mirrored bones while defining the armature.)

For pre-2.40:

First make the armature so that it is complete for one side (say, left). All the side-specific bones should end in .L, e.g.: UpperArm.L, LowerArm.L, etc…

Simply name bones that don’t have a side without any extension.

In Object Mode, select the armature, Shift-D to duplicate it. Scale it by -1 to mirror it. Now you have to do a little work. Tab into edit mode and delete all the bones that don’t have a mirror. Rename the bones that end in “.L” to “.R”.

Back in object mode, select the duplicate and the original (in that order) and Ctrl-J to join them. You’ll have to do a little more work again in edit mode to link all the mirrored bones back into the proper hierarchy and with the proper constraints. Don’t forget to press Ctrl-N --> Recalculate Bone Roll Angles before leaving edit mode.

Now, when in Pose Mode, you can select all bones and press the Copy to Buffer button. Change to your desired frame and press the Paste Mirrored Pose from Buffer button. Ta-da!