Below is a link to an article from the Immigration Policy Center of the American Immigration Council which goes through many of the myths about Immigration and the economy and explains why they are incorrect.
For the most part, immigration actually helps our economy, does not depress wages, and actually stimulates growth of the economy and of job opportunities. They also point to several studies that show that there is no correlation between immigration and unemployments in general, and minority unemployment specifically. In addition, they cite to data from the 2012 Current Population Survey that show that, for the most part, immigrants and native-born workers are not competing for the same jobs, thereby dispelling the myth that they are taking jobs from US workers. I think that the article is definitely worth reading for those interested in this topic.