Here's the short version:
Quadaffhi's goons severed the main hub that was the backbone connection for all of Libya's cellular network infrastructure. It was designed in such a way that all voice/data traffic was routed through the capital for snooping and management reasons. When Khadafi's regime started being overthrown by rebels, he cut the cables effectively reducing his enemy to a system of flags and smoke flares for communication.
So what happened? With the majority of the network infrastructure in place (just not a way of connecting to the rest of the internet) hackers gave it a new uplink (via U.A.E. and Qatari-funded satellites). They even went as far as extracting the old number/subscriber ID information from the Tripoli based servers in order to import them into this new database. Suddenly, those "can you hear me now" ads seem stupid.
I wonder if they bothered with visual voicemail or an app store?
Source -> http://www.popsci.com/technology/article/2011-04/massive-hardware-hack-libyan-rebels-hijack-disabled-cell-phone-network via http://online.wsj.com/article/SB10001424052748703841904576256512991215284.html?mod=fox_australian