Lebanon has been a pretty tense place after Israel destroyed the credibility of the pro-American government and solidified Hezbollah as the dominant force in the country, but last week has been tenser than most. Hezbollah seized control of half of the capital city from its pro-American Sunni political rivals (they all have militias) and the fighting is spreading, on May 11th Hezbollah complied with army demands and withdrew from the areas they had seized.
The sporadic fighting through out the rest of Lebanon is probably motivated be multiple factors and doesn't have all that much to do with the central government vs. Hezbollah conflict. What is disturbing was the speed with which Hezbollah was able to take over, I can not stress this enough, half of Beirut without much effective opposition from the other political parties. What is highly confusing is why Hezbollah bowed to the demands of the army - the army would be no match against Hezbollah - why should they let themselves be pushed around?
Best guess is that Hezbollah knows it will likely eventually dominate the political infrastructure of Lebanon and wants to inherit an intact state. I am curious to see how this will turn out. I think to whatever extent possible we should help out the Lebanese army in this, throw em a couple helicopters or something.