BP says that it's stopped the flow of oil into the Gulf, at least temporarily. They're currently pressure-testing a new cap on the Macondo well. The idea is to cut off flow from the well entirely in order to see whether there are leaks below the seafloor. If those leaks exist, pressure won't hold and the oil could start flowing out from other places. There's also a risk that cutting off flow at the cap could actually create those sub-surface leaks by building up pressure too fast. The test will last 48 hours. If everything holds, it could lead to a permanent capping.