There's a lot of money to be made off illegal activity, and the U.S. Federal Reserve (FAQ) is trying to get a piece of the pie. The subscriber-only WSJ article "U.S. Banks Woo Migrants, Legal Or Otherwise" has this preview:

As U.S. leaders craft policies to curb illegal immigration from Mexico, the U.S. Federal Reserve is devising programs to extend banking services to undocumented immigrants. A new remittance program aims to bring Mexican migrants who send money home into the mainstream U.S. financial system, regardless of their immigration status.

Dubbed "Directo a Mexico," the remittance program enables U.S. commercial banks to make money transfers for Mexican workers through the Federal Reserve's own automated clearinghouse, which is linked to Banco de Mexico, the Mexican central bank.

To use the service, a Mexican need only possess a matricula consular, an I.D. issued...

Expect the crooks behind this program to use everything they've got to support it should it meet any opposition. That will include everything from playing the race card to playing the terrorism card. But, the bottom line is that they're willing to put making money ahead of everything else, including their loyalty to this country.

The federal government profiting from, enabling, and encouraging illegal activity is an extraordinarily dangerous situation and undermines our entire political system.

I urge everyone to try to bring this program to wider attention through the internet, calling in to radio shows, attending speeches by politicians and trying to get them to publicly oppose this scheme, and similar.

UPDATE: A longer excerpt is here. See also the April 16, 2004 speech "Financial Access for Immigrants: The Case of Remittances" by Ben Bernanke. At the time he was a governor of the Fed, now he's the chairman. It discusses "immigrants", but does not contain any instances of "illegal alien" or even "undocumented". However, this quote makes clear that he is considering both legal immigrants and illegal aliens under the same "immigrants" banner:

...Concern that opening a bank account may require proof of legal residence may inhibit some immigrants from doing so (in fact, many banks now accept foreign-provided documents such as the matricula consular); but lack of knowledge about the services banks offer and the fees they charge is likely an important factor as well...

UPDATE 2: The Federal Reserve Bank of Richmond's "Region Focus" magazine from Summer 2006 puts a bright smiley face on illegal activity with "The (Illegal) Immigrant Effect" by Doug Campbell of the bank. He's also the author of "Searching for the Hidden Economy" from their Spring 2005 edition. While both articles discuss the downsides of illegal activity and studies such as those from Borjas, one is struck by, shall we say, the lack of a moral compass. And, the first article also contains this whopper:

Perhaps the only thing that can be said with certainty about immigration's economic impact is in identifying its main beneficiaries: They are the immigrants themselves, people like Javier.

I guess it boils down to how you define "main". Obviously, those who employ illegal aliens are making scads of money, as are those who are trying to tap into the flow such as major banks and even the Federal Reserve.