This is how you do it. There's a reason Animal Farm is a classic of both literature in general and political satire specifically - it's damn near perfect. The allegory is simple enough for a literate child to grasp, even if they have no information about Stalinism or Soviet Communism to base it on, and for those who have studied history it maintains its worth as a fable.
The telling of the story itself can scarcely be criticized. You know what's going to happen. It's obvious from Napoleon's first appearance that he'll soon be as much (or more) of a tyrant as the original farmer. Heck, I'd read it before, back in middle school, but I still felt the rush when the animals drove out their owner and burned the whips, seethed with anger at Squealer's endless propaganda (swallowed whole by the mostly-illiterate and trusting workers), shared Benjamin's rage and horror as Boxer is sold to the knackers to pay for the pigs' carousing.
I believe it was Terry Pratchett who said something like, "There's a reason they're called revolutions - it all just keeps coming around to the beginning again." What I found interesting, though, was that the book really isn't a flat out condemnation of socialism or even communism - it's about a promise broken, power seized, and ideals twisted into a horrible shape. I think that's part of why, even while USSR-style communism fades into history, you can apply the Animal Farm allegory to any number of political situations. It's not strictly tied to the obvious.
final thought: This book scared the crap out of me as a preteen. (I was already fairly paranoid and antigovernment way back then.) These days I find it less frightening, but I think it maintains a current of power found in very little political writing.