Had a couple of comments / e-mails commenting on sorties over Libya. I am no expert on tactics however I think I can summarize it for you.

In order for NATO forces to establish an enforceable no-fly-zone, NATO assets need to ensure that they have unrestricted access to the zone. It is therefore necessary to first incapacitate Libyan command and control, radar (long-range and fire control) installations, surface to air defenses and aircraft that could intercept and potentially engage NATO assets. The sorties are designed to accomplish just that, using cruise missiles and NATO aircraft. Once Libyan defenses have been suppressed, NATO can patrol the no-fly-zone, providing a buffer between the rebels and Libyan forces.

If successful, it creates an opportunity for a cooling down period so that a diplomatic solution can be implemented – doubtful given the actors in the region.