Can you record a phone call with the iPhone 4's?

I downloaded TapeACall, but ended up deleting the app because it only lets you listen to the recorded phone call for the first 60 seconds. I really need to record a phone call for my English class, as I'm interviewing someone over the phone. Do y'all know of any apps that let me call someone, record the phone call (allowing me to here myself and the person on the other line), or a way to do this without getting an app? Any info would help!

Hi
I would like to recommend these apps.
-TapeACall Lite
-Google Voice
-Call Recording by NoNotes.com
-PhoneTap
-TapeACall Pro - Record Calls
-Call Recorder - IntCall
-Call Log Pro
All these apps are very useful.