[drheath]

My bad, I thought you wanted to display information. I did something a while back that disabled specific shipping options based on extra field values of cart contents, but I really don't remember the details. I'm sure I found the instructions on the forum, it may help point you in the right direction.

If your only requirement is order total must be over 12 lbs, you could just set the minimum value on shipping options at 12 lbs and change the error label to read something like "Your order must be at least ..." The customer would not be able to check proceed without selecting a shipping method. If you did that, you may want to include the weight in the cart display.