I pre ordered the season pass from GameStop, I have 4,000 Microsoft points to purchase the season pass but there is no option to purchase it?
The season pass is not out yet. There wont' be any DLC until 2013.
As far as I know, since you pre-ordered from Gamestop you will have to buy it at Gamestop so the amount of MS points you have doesn't matter.
I was just able to purchase it. I went to xbox.com and went to the Black Ops page. From there I clicked the marketplace link. The season pass can be found about four or five items down the page.