Here is a listing of the average starting and mid-career salaries for most 4 year majors.
http://www.payscale.com/best-colleges/degrees.asp
The ones with the highest salaries are the ones in the most demand by employers. And the higher they pay, the harder they are. And remember this survey only covers the students who got a job in their field of study. The lower paid the job on this list, the few the number of graduates in a particular major got a job in their field.
http://education.yahoo.net/articles/six_in_demand_degrees.htm?kid=12X5N
The Highest Starting Salaries of 2010
http://hotjobs.yahoo.com/career-articles-the_highest_starting_salaries_of_2010-1296
