If there isn't an app you deem decent, make an unattractive, bulky hardware solution. At least that was this guy's idea. Apparently making a switch box was the only way to inconspicuously record iPhone calls.
It's actually impressive to see how much planning went into this iPhone call recorder. Since time is money, we are gonna say shelling out the money for apps like Recorder 10 or SpoofApp (though requires jailbreaking) is worth it. [Make via AwaitingInspiration]