In case if you did not know it yet, some money market funds have joined the U.S. Treasury Temporary Guarantee Program for Money Market Funds program, meaning that all your money, as amount at Sept 19, are insured for government. Not for all MMF, some only.
One example:
http://personal.fidelity.com/products/funds/content/FidelityMutualFunds/articles/money-market-funds.shtml.cvsr?fca_id=20084341p01