Whoever said supplies aren't important is about as wrong as could be. The rebels are running dangerously low on fuel. Remember, they're waging their war in a fleet of Toyota pickups. All the hit-and-run fighting between Ra's Lanuf and Bin Jawad the last few days, and the fact that they have to drive hundreds of miles to get from Benghazi to the front lines, eats up a lot of gas. Even though they control some major refineries and oil terminals in the East, all the foreign workers who staffed them have been evacuated. Food and medical supplies in the besieged cities of Zawiyah and Misrata are critically low. If you look at the history of the Afrika Korps in WWII fighting in this exact same area, the whole thing came down to logistics and stretched supply lines. Rommel could only push so far, because his supply lines got overextended. Montgomery could only counter-push so far, for the same reason.
Honestly, if NATO/UN wants to help and stick by the weapons embargo and avoid the messiness of a no-fly zone, then start shipping fuel tankers to Benghazi. They're already supposedly in talks to obtain fuel from Italy. (Of course, with domestic fuel prices soaring in many countries, there would be the inevitable backlash by domestic opposition...)
There was some odd dueling reports about Qaddafi supposedly offering to step down in return for immunity from prosecution, but the NLC said they rejected that offer, then later an official told the AFP they were offering that to Qaddafi, then Qaddafi's government denied any such offers had been made in either direction. Not sure what was going on there. And I can't see many of the rebels being willing to accept those terms. They want a free Libya, but they want justice/payback as much as anything.