this article (in french) is among the more extensive analyses of moussa koussa's defection:
Libye : fin de règne pour Kaddafi ?
the gist of it is that koussa has been close to gadhafi for over 30 years and is the last of the inner circle---apart from his sons. most of the commentators who are cited in this piece take the defection as meaning that the regime's days are numbered.
before becoming the foreign minister in 2009, koussa was for many years head of libyan intelligence---so the head of the gadhafi's secret police. this guy knows. there is no-one with more comprehensive information about the gadhafi regime than this.
what's remarkable is that he defected without a guarantee of immunity just after handing in his resignation, according to the article. it's not yet known how he managed to get out of tripoli----gadhafi apparently said repeatedly that "we are all prisoners here"----which is oddly close to that vile eagles song. but i digress----the article says that the current head of libyan intelligence---aboud dourda---is also on the run. it says he's being shuttled out of libya by way of the russian embassy. there's different speculations about where he'll land.
the trigger for these departures publicly is disgust over the violence of the campaign against civilians. i'm sure that's a part of it. i suspect there are other factors too, not least must be some kind of calculation about how the endgame is going to go.
if all this is correct, then it would appear that gadhafi's situation is crumbling from the inside. but given the way it's organized, and the centrality of his kids in running the show that remains, it's not obvious how much further in the crumbling process things need go following on these departures.
there's other stuff in the article, but that's the gist.