For conspiracy, there is no imminent proof of that so I won't relate this with any conspiracy. But then this is politics too and there are cent/cent chances of conspiracy
But as far as people being happy and suddenly rising, NO they have enough reasons. Someone who have been ruling the country for such a long period should have made it a bit better by now. There was a time when people were happy because US aids to Gaddafi used to brought money in the country and so a better life. But recently it stopped and recent global inflation worsened the matters. Now more people were suffering due to poverty, lack of opportunities and they were angry on Gaddafi that all these years he did things just to last temporarily. Country did improved in his reign but not as much as you would expect from someone ruling for so long. (Yet again since it a poor country in terms of economy or local; conditions, so Gaddafi never had clear chances either)
But if he's removed from the power and some other military guy takes over, things would change at least for sometime. See Gaddafi was never a democratic leader and nor would be the coming army men. But there would be inflow of dollars as U.S. would be keen to help the new leader and would make him come to thier own favorable terms like exploiting Libya's natural resources and in reply give some dollars. That had been struggling U.S. policy recently or at least it seems to me.
And one more thing, U.S. had been denying that they are not related with recent bombing on Libya, only they have agreed with EU's decision. US didn't want to mess in Libya. Robert Gates had said so much openly. Its more a French initiative this time. ANd the US has tagged along after deliberation. The key point to remember is that while Ghadaffi might be evil, he is not attacking anyone else and is only trying to crush a revolt within his own country. I feel a very dangerous precedent has been set by this action. I think UN should obey national boundaries and sovereignty. Action was needed when the guy did something evil, not on the pretext that he might do something evil. There is a major difference between the two.