Cluster bombs can't be aimed:

Because the fragments travel at high velocity, when they strike people they set up pressure waves within the body that do horrific damage to soft tissue and organs: even a single fragment hitting somewhere else in the body can rupture the spleen, or cause the intestines to explode. This is not an unfortunate, unintended side-effect; these bombs were designed to do this.
[...]
Because cluster bombs disperse widely and are difficult to target precisely, they are especially dangerous when used near civilian areas.

The image that Nicko posted is from Basrah, where such weapons have been deployed in the last days:

A surgical assistant at the Saddam hospital in Nassiriya, interviewed at a marine check point outside the city, said that on Sunday, half an hour after two dead marines were brought into the hospital, US aircraft dropped what he described as three or four cluster bombs on civilian areas, killing 10 and wounding 200.