回复：我替我岳父母申请税号, 填W-7表问题

it doesnt matter you or your wife's name if you file a joint return. The caution part means IRS requires if you need apply 税号, usually you cannot apply early, you need submit your 2005 tax return and W-7 together to the address W-7 instruction shows instead of 1040 instruction mentions (usually in PA state), they will process your W-7 first , mail you the 税号and then process your 1040 tax return. just leave the 税号 for your parents-in-law blank in your 1040 dependent part.