The SICC, Somalia's Taliban, have been engaged in a war with the secular national government which called in Ethiopian help. In fighting that began a week ago well-trained Ethiopian forces with MiGs and tanks along with Somalian government troops have routed the Islamists and driven them back into Mogadishu their base of operations. Troops have advanced to within 15 miles of Mogadishu though the question remains whether the city will be besieged or taken by force.
Cliff May has some thoughts on why Ethiopia is winning
More “boots on the ground” may be part of the explanation. The Ethiopians are not attempting to have a “light footprint.” They are not worried about whether they will be seen as “occupiers” or whether their “occupation” will be viewed as benevolent.
Secondly, the Ethiopians are not overly concerned about whether their tactics will win approval from the proverbial Arab Street – or the European Street or Turtle Bay. They are fighting a war; their intention is to defeat their enemies; everything else is secondary or tertiary.
Also the SICC hasn't made itself popular by sending primarily adolescents into the fight: [from the NY Times]
Ahmed Nur Bilal, a retired Somali National Army general, said the war had been a horrible miscalculation. What made him especially mad, he said, was the Islamists’ reliance on adolescent boys to do most of the fighting. One of the first things the Islamists did after the fighting started was to close all schools in Mogadishu to send more young people to the front. Witnesses to some of the battles said the teenage troops were no match for the better-trained, better-equipped Ethiopian-backed forces who summarily mowed them down.
Ethiopia intervened at the request of the Somali goverment but it's reasoning is clear - bordered to the north by a hostile Islamic Eritrea, an Islamist insurgency to the south has been judged to be inimical to the interests of the country strategically so a pre-emptive attack makes sense.
Islamists in Somalia are likely to include elements of al-Qaeda so the West has a stake in this struggle hence the tacit US support for Ethiopia. Hopefully Ethiopia has learned the lessons of Falluja 2004 - crush this insurgency utterly rather than submit to some idiotic power-sharing agreement and leaving a festering Sadr-like abscess.