The FDIC announced their final rules on the so-called Temporary Liquidity Guarantee Program, or TLGP (Pronounced "Teelgup"). This is the program that was designed to allow banks to issue FDIC insured debt, ensuring that they'd be able to roll over any debt coming due in the coming months.
The key change in the final rules is that the guarantee will now be timely principal and interest. Under the original rules it would be possible for an investment in a failed bank to get tied up in bankruptcy court, and while the FDIC would eventually pay you, there was no assurance as to exactly when.
This debt will now carry a full faith and credit guarantee for as long as three years (6/30/12 to be exact). Note that similar debt has been issued in Europe, most notably Barclays who did the first deal in the U.K. That deal was priced at swaps +25. I expect U.S. debt to come wider. To me, its got to trade in context of Agency bonds, which are more like swaps +50, Treasuries +165.
There are three interesting wrinkles here. First, the FDIC bank debt will be explicitly guaranteed, while Fannie and Freddie are not. However, I'm hearing the FDIC stuff will have a 20% risk weighting for banks. That's equal to Agencies currently, but there has been talk that the Agencies will be reduced to 10%.
Finally, there will be extensive supply of the FDIC stuff over the next month or so, whereas the Agencies have done very little term issuance. So given the market's poor liquidity, I'd expect the new FDIC issues to have a new issue concession, and therefore price wider than Agencies.