mirror weights to other bone

I was wondering if there is a script or something that transfers weights assigned to vertices for bones over the the corresponding bone on the other side. So for example, transfer the weights for arm1.R to arm1.L

Isn’t one bundled with blender? Scripts/Mesh/Mirror vertex locations and weights. I haven’t used it on a real model, but a quick test shows it works fine.

Thank you ondrew, I knew someone out there would know. You saved me a lot of time.