Oz,
minimum requirements are a movable feast depending on the airline and the state of the market. In UK (and, I'd guess, the US), because there are a large number of experienced pilots on, or about to be on, the market, minimum requirements are rising. A year ago, 200 hours and a frozen ATPL would have possibly got you a job on a 737. Now, the same airlines are looking for 1500 hours. This will reduce as those experienced pilots are absorbed.
A 'frozen ATPL' refers to a situation where a person has passed all the ground and air exams for an ATPL but has yet to achieve the qualifying flying hours. Thus he/she is awarded an ATPL frozen (ie you are unable to exercise the privileges attached) until those hours are achieved. I believe this situation only exists within the JAA sphere of influence.