The Center for Immigration Studies has released a new report on the so-called Hispanic vote in the 2008 elections (link). A few key points:

* The drop in support among Latinos for Republicans between 2004 and 2008 was part of a broad-based electoral movement away from the GOP, and was hardly specific to that demographic group. McCain received only 57 percent of the white male vote, compared with 62 percent for Bush in 2004, and McCain’s 55 percent of regular churchgoers was significantly lower than Bush's 61 percent.

* Credible surveys indicate that the major policy concerns of Latinos were no different than the concerns of non-Latinos: The economy and jobs topped the list.

* There is little evidence that immigration policy was an influential factor in Latinos' choice between the two candidates once basic party predispositions are taken into account.

* McCain's consistent history of advocating a legalization program for illegal immigrants made no impression on Latino voters.

UPDATE: From the other side, the Immigration Policy Center has responded with some polling data linked from here:
lawprofessors.typepad.com/immigration/2009/01/fact-sheets-by.html
The surveys they point to were performed by Frank Sharry's America's Voice, the Illinois Coalition for Immigrant and Refugee Rights, and others and may have been designed to show what those groups wanted them to show. The IPC fact sheet also doesn't address general election trends.

UPDATE 2: The CIS author responds to his critics here.