Popular Mechanics posted the results from the UK Ministry of Defense's Grand Challenge.
It is my longstanding prediction that UAVs will become ever more prevalent on the battlefield, to the point where they fulfill the majority of air attack and ground support roles.
This, in turn, will have profound influence on the worldwide balance-of-power, becoming one of the most important force multipliers available to US forces. This will also make electronic warfare, in particular signals disruption, satellite (GPS) interference and network penetration, key avenues for the enemy to pursue.
In particular, a single soldier far from the front lines might control a swarm of UAVs, directing the swarm to overwhelm its target. Or, the soldier might sit at a console, making a stream of yes/no kill decisions, and assisting with automated targeting systems. The Popular Mechanics article describes swarming behavior with several of the drones participating in the Grand Challenge.
Finally, while I'm on the subject, StrategyPage published a UAV update (for US forces) recently, Rise of the Droids.
Update: Just after posting the initial draft, SP published another UAV update. In short, they are highly effective and everybody wants more. The MQ-9 Reaper, a combat UAV with recon capability, will eventually supercede the MQ-1 Predator (primarily a recon UAV).
US troops are developing new tactics based on the UAV's ability to keep an area under surveillance for an extended period of time. Presumably the same will occur as combat UAVs like the Reaper become more prevalent.