therethere, my employer-provided health care insurance was also blessed with a spousal surcharge, $25 per biweekly paycheck. On my paycheck, it is listed as a Before-tax deduction, right next to medical, dental, 401k, etc. Now I haven't actually prepared federal taxes with this surcharge in place, so I can't say for certain whether it ends up being pre-tax, but at least my company believes it will be.
Also, these spousal charges are no doubt going to be ubiquitous soon, after all, once a few companies start pushing the spouses of some of their employees off of their plans and onto the plans of other companies, there will become clear winners and losers in this setup, and the rest will follow suit.