It looks like Congress doesn't know what to do about Libya. On the one hand, they are frustrated that President Obama hasn't asked permission for his actions there, on the other hand they don't want to publicly say that he can do what he's already doing (see story here). The real question is, does the president have the authority.
The War Powers Act came into being when Richard Nixon was in power and the Vietnam War had been going on forever. John Kennedy sent troops there and the US never officially declared war. Congress tolerated it through his short time in office and through Johnson's. After Nixon became president, Congress decided to tie his hands.
Presidents since then have complained about the constitutionality of the law. But they also followed it. There seemed to be a delicate balance of power, not completely unlike what the framers of the constitution wanted. President Obama has stated that he didn't think the law applied, the biggest reason being that we don't have troops on the ground.
Actually, I support the president on this, but there has to be some caution. The next president (in 2012 or 2016) may be a Republican and may use this argument also. In fact, I've found myself agreeing with the president a lot more lately, his decision to surge in Afghanistan, his decision not to pull all troops at once, his decision to leave troops in Iraq, his decision not to close Guantanamo. I think he's come to the realization that this presidential job is a lot harder than he believed when he asked for the job.