TOEFL (test of English as a foreign language), is a required exam for almost any college in an English-speaking country. In the times I was taking it, almost 10 years ago, they were asking for a score of 550-600 (paper-test) for acceptance. It is a reasonably straight-forward test. As Чиффа reminded me, the results of TOEFL are only valid for 2 years, so one should only take it if one expects to need it shortly.
General information about the test:
www.ets.org/portal/site/ets/menuitem.1488512ecf...
Free question samples at the link below.
www.ets.org/portal/site/ets/menuitem.1488512ecf...