I deplore the use of cluster bombs and cannot excuse the Israelis for using them. It doesn't make sense to me that they would do something that would so obviously be seen by the rest of the world as illegal. It is very puzzling. The one reason that I can think of is that it was done to slow up the repatriation of the Lebanese who travelled north to get away from the war, and give Hezbollah something else to do, rather than fire more rockets at northern Israel.

But I did find this section quite interesting in surasak's link to the Geneva Convention:

Article 51: Protection of the Civilian Population

1. The civilian population and individual civilians shall enjoy general protection against dangers arising from military operations. To give effect to this protection, the following rules, which are additional to other applicable rules of international law, shall be observed in all circumstances.
2. The civilian population as such, as well as individual civilians, shall not be the object of attack. Acts or threats of violence the primary purpose of which is to spread terror among the civilian population are prohibited.
3. Civilians shall enjoy the protection afforded by this Section, unless and for such time as they take a direct part in hostilities.
4. Indiscriminate attacks are prohibited. Indiscriminate attacks are:
1. those which are not directed at a specific military objective;
2. those which employ a method or means of combat which cannot be directed at a specific military objective...
I think Katyusha rockets easily fall (no pun intended) into the latter two categories.