It all depends on how the job is classified. If it is classified as professional or managerial, it probably is not eligible for overtime. In my company (major insurance co), all full time workers are salaried. Your job is classified as "exempt" (no overtime, no time records except for vacation or sick) or "non-exempt" (eligible for overtime, careful time records have to be kept). There are laws regarding eligibility for overtime. I've heard of companies who had to give backpay because they inaccurately classified workers as not eligible for overtime. There are also laws regarding comp time. In my company, the comp time has to be taken in the same week in lieu of overtime pay.
Unfortunately, I am in the "exempt" category. I got up Monday morning at 3:00am for a 6:00am flight to MN and did not return home until 11:00pm Tuesday night. No overtime or comp time.