He's taking the ACT next Saturday (June 2010). His sister just finished her first year of college; her first time taking the ACT was also at the end of her sophomore year. Where we live most students just take the ACT - my daughter took some SAT subject tests because one college she was applying to required them, but very few students here take the SAT.
He's mainly going through some sample tests so he is familiar with the format and the pace.
Good luck with your studies!