Not only is this a good idea with a dev and a QA working together we have found within our own QA that 2 QA testing together you will hit issues neither of you have hit together. This is because you are both different testers and will test differently and so together you will try things neither have thought of. Also you will be able to track down more detail since you both have different ways to figure out the issue. You can also write a very thorough Test Plan if 2 of you work together to hit all the test cases. So do I feel Paired Testing is the wave of the future? I believe I think it is.
To know more I suggest you go to Http://softwaredevelopmentisfun.blogspot.com/2008/07/pair-testing.html