Pakistan is predominantly Sunni and Iran predominantly Shia.
Iran were pretty co-operative with the US post-9/11 re Afghanistan, and I certainly don't see them as pro-Taleban, who regard the Shia' as apostates. "Any economic unit can emit money. The serious problem is to get it accepted" Hyman Minsky
then, there are the Pashtos which are mostly Afghan/Pakistani
If you haven't heard of the Indian-Pakistani fight for influence in Pakistan, I will look up a few references for you, but I thought it was pretty common knowledge
http://en.wikipedia.org/wiki/Persian_people
