Pakistan has more police and troops along the Afghan border not just to help find al Qaeda and Taliban leaders, but to stop the growing amount of opium and heroin coming into Pakistan. There has long been a drug problem in Pakistan, especially in the cities. Pakistan successfully shut down most of the drug production activity (in its north west) in the 1980s. The drug business moved across the border to Afghanistan. All Pakistanis (even some of the users and producers) agree that the drugs are bad. But there's a lot of money involved, and that keeps the drug gangs, and tribes that support them, in the business. Both the Pustun tribes in the northwest, and the Baluchi tribes in the southwest, are involved in the drug business. Some production has returned to Pakistan, but most of the Pakistani tribes are involved in smuggling and distributing the drugs. Apparently, al Qaeda and the Taliban members are also working in the drug business as well, in order to raise money for their cause.
The US FBI and CIA people operating in Pakistan, along the Afghan border, keep an eye on the drug trade as well as the search for al Qaeda and Taliban. There is much talk that two years of effort will result in the capture of Osama bin Laden and Taliban leaders sometime this year.