As the US looks to spin down its campaign in Afghanistan (looking towards draw-downs in 2011), it has two current objectives towards which it is racing:
1) Eliminate and prevent the resurgence of al-Qaeda links in the AfPak region that can contribute to worldwide terror attacks.
2) Sufficiently reduce the influence of the Taliban that it cannot take hold and later become a stable harborer of terrorism / Global Jihad.
Unfortunately, these two objectives stand in some conflict, particularly where Pakistan is concerned. Pakistan largely lacks the capacity to hit al-Qaeda targets in its northwest on its own, so the United States has been sending "covert" drone attacks over the border to eliminate them. This alone seriously increases tensions, but worse was that a drone attack recently killed 3 Pakistani soldiers by mistake--US-Pakistani relations are often strained, and should they break the US would lose what intelligence and military support it has against militants in northwestern Pakistan, which serves as a "safe zone" for the Taliban to retreat, regroup, reorganize, refresh, and re-enter Afghanistan anew.
The US is pursuing its two objectives with two very interesting campaigns.
The first: Petraeus is launching a full-scale Counterinsurgency campaign, actually much different from the combined COIN/civil war stabilization/insurgent-hunting programme used in Iraq. The strategy is a full "take-and-hold" style campaign, in which the US simply "moves in" to Taliban-heavy areas and tries to install a local government and security force--area by area (rather than seeking out and killing the Taliban). The campaign has met limited force-to-force resistance so far, mostly because full battles against NATO forces fare poorly for the Taliban--they continue to use hit-and-run or booby-trap tactics to wear down NATO as NATO tries to win hearts & minds with security & handouts.
The second: The CIA (with the President's go-ahead) has stepped up drone attacks on Pakistani soil to new highs--in its most recent publicized attack, the CIA killed 5 German militants, just after news broke that European citizens were part of a planned string of Mumbai-style attacks in Europe (this particular attack not only disrupts al-Qaeda in Pakistan, but likely does well to partially shore up confidence from the US' European allies that its presence in the AfPak region has the potential to make them safer). This campaign is likely tactically very effective--it is diplomatically extremely costly, and would be an unlikely direction for the Obama administration to take if it didn't seem to have a military effect.
To be fair, Pakistan is still looking towards a full campaign into the Waziristan area (after a relatively successful campaign in the Swat area), but it is not ready. Floods throughout the country have tied up much of its military (in relief efforts) and drawn attention away from the Taliban threat. If-and-when Pakistan moves north towards the Taliban strongholds in Waziristan, the tide of the battle may turn. Sadly, I've been saying this for a long time.