The best analysis I've seen so far of the Shirley Sherrod incident comes from David Frum, whose recent commentary on conservatism has been especially astute. Aside from an unmerited swipe at Dan Rather, there's not much to disagree with there.
What's missing so far, I'd say, is that not many liberals have seen this as the golden opportunity to strike at FOX itself that it surely is. The conservative movement long ago took a structural approach to battling liberalism: attack the institutions of liberalism and of rational discourse and you weaken your opposition. Hence the endless slandering of unions, universities, social security, the establishment media, etc. Doesn't matter if the complaints are true, just repeat the grievance and eventually the narrative will sink in. Liberals, maybe because of their greater ideological sympathy for pluralism, free speech, and fair play haven't had much stomach for reciprocity in that kind of battle. But here's a case that exposes the rotten core beneath FOX News in an especially glaring way: a racially motivated hit piece against an innocent (and even noble) public servant. Why not denounce their behavior and then hammer it home? For Pete's sake, they fumbled the ball in their own end zone. Fall on the ball!!!
It never ceases to amaze me that other news outlets treat FOX as if they're just another set of concerned and objective "journalists," albeit conservative-leaning ones. FOX has been pushing their luck for quite some time now. It wouldn't take much for liberals to take them down a notch--just some guts.