Iona College in New Rochelle has expanded its Link program to add seven more high schools in the past two years. The program, which is now available to 19 high schools in Westchester and New York City, allow students to get a head start on college work at a fraction of the cost. A freshman writing course at Mamaroneck High School, for example, costs $75 a credit, as opposed to $850 a credit for regular Iona students.