It's more than a little ironic that 70 years after Rommel's forces started moving against the British forces not far from Benghazi there's a new deset campaign shaping up on roughly the same battlefield.
While I think the politics behind this intervention are very problematical (yet another war?), militarily the situation is considerably simpler than either Iraq or Afghanistan in an immediate sense. Command of the air is vital in any land campaign, but never more so than in the desert. I don't think there's any question that Western aircraft can make it essentially impossible for Gadhafi's forces to either fly warplanes or mass heavy firepower like tanks and artillery anywhere near Benghazi. I'd expect the No-fly zone and associated "no-drive" zone to have an immediate and dramatic impact on Gadhafi's forces. While it's likley he could still try to take Benghazi with lighter forces (technicals and the like) it's also likely that these wouldn't be enough to root out the rebels who are similarly armed.
What's missing, of course, is a strategic context for all this and what's desired for an end state. It seems that the rebellion never mustered enough support from the key Gadhafi strongholds around Tripoli and I therefore doubt they can win control of the whole country anytime soon, if ever. History cautions us that these sorts of things can dra out for a very long time indeed.