In my experience, the best way to freeze baked cookies is to individually wrap each in press and seal freezer wrap (you can double wrap them if you want), then store them in an airtight tupperware container or gallon sized freezer bags. I have done this with chocolate chip, oatmeal cookies, sugar cookies, and tea cakes. I have kept them frozen my in deep freeze for up to 2 months and they have tasted completely fresh after being thawed.
~Heather~ Mom to Brittney (12-12-05) and step mom to Liz (12-28-04) and Brandon (7-28-99).
Check out my sweet treats photobucket: http://s649.photobucket.com/albums/uu217/sweettreats05/