Hi
I'll try to make it simple: First of all, you should know that education in the states is extremely expensive and can reach tens of thousands of dollars per year. To make things worse there is no financial aid for foreign students and those who are not US citizens. Second, if you know what you want to learn, you can contact the 'Fulbright' foundation in Israel, and they will help you thruogh the process. They have an office in Tel aviv. You should be aware that the whole process from begining to end can last at least a year, in most cases even 18 months and is very expensive also. You will probably have to take several tests in english and math and be prepared for a real headache. The visa issue in this case is the easiest part and if the university wants you, then you will acquire the F visa that allows you to live in the states but not to work. Hope I helped.
