In short, here's what's going on: Islamist terrorists held an uprising in Mali. Concerned France launched a ground attack to stave off the terrorists. Algeria helped France. Terrorists took revenge on Algeria by taking hostages at a BP gas field. Algerians attempted a hostage rescue. Hostages killed, some survived. Some terrorists killed.
Update: Hillary's press conference prior to the rescue attempt:
Update 4:15 pm ET: Some hostages killed in Algeria. Another report says 34 hostages and 15 kidnappers were killed. And yet another report.
More on this here. A primer here.