I came across the following on Winds & Breezes and just had to post on it. According to Salary.com, Stay at Home Moms in the U.S. would earn $134,121 p.a.

If paid, Stay at Home Moms would earn $134,121* annually (up from 2005′s salary of $131,471). Working Moms would earn $85,876 annually for the “mom job” portion of their work, in addition to their actual “work job” salary.