From this:

A top foreign relations official on Thursday lambasted California Gov. Arnold Schwarzenegger's veto of legislation that would have allowed undocumented migrants to obtain a driver's licenses in the state...

Juan Bosco Marti, general director for North American affairs with the Foreign Relations Secretariat (SRE) said in a press conference the Mexican government is very concerned by the action.

Bosco said the inability of undocumented workers to obtain a driver's license hurts all migrants in California, not just Mexicans.

"The Mexican government will continue to defend the interests of the Mexican community residing in California within the realm of the laws of the United States and California," he said...

Bosco said the Mexican government would continue to promote the use of consulate-issued I.D. cards to help give migrants in the United States a means of identification that they can use to obtain U.S. drivers' licenses, bank accounts and other services.

The SRE says the cards are accepted as valid identification in 33 U.S. states, 1,180 police departments and 178 banks, and that it has issued 2.2 million of them since March 2002.

See also "California legislators ask Mexican Senate to intervene [in driver's licenses for illegal aliens]"

For more on the Matricula Consular cards, see "Their money or your safety".