We went to see Prince Caspian with the kiddo - it just came out yesterday. I am surprised we have been able to hit the theater twice in one month seeing as it was like ten since we've gone.

You should definitely not watch this movie if you haven't seen the first, as scenes where they refer to the first (extraneous and pointless in the case of the "witch" scene) would be total nonsense to you otherwise.
Prince Caspian is the sequel to the first Narnia movie, and this action takes place in Narnia hundreds of years after those events, though the main characters have only aged a couple years or so in the real world. If you can understand that sentence, these movies are likely up your alley. Peter, Susan, Edmund and Lucy all return in their mythical roles as the queens and kings of yesteryear as they do battle against the new foes that have kept the peaceful, albeit often unattractive, denizens of Narnia in hiding. They join up with Prince Caspian who is ousted by an evil power hungry uncle along with a bevy of critters and "little people". The movie is so similar to Lord of the Rings that I expected a couple hobbits to show up, but no dice.
Our young heroes focus is to do battle against the oppressive regime, but the battle scenes are confusing at best. Also, I am not sure if it is supposed to be funny to watch centaurs clip clopping at high speeds brandishing swords, but it was. There are some touching moments, particularly with the youngest kid Lucy as she bonds with some of unlikely friends in this otherworldly habitat, but I felt that the rest of the picture was lacking in emotion, other than bouts of anger. One of the best parts about the first movie was watching the younger boy, Edmund, betray his siblings and redeem himself. In this movie, everyone's just arguing and fighting.
It's a violent movie and one should consider this with the younger family members. One should also take pains to get your needs met prior to the film as it is long. If the kids liked the first one, they'll likely enjoy this one, but if you think it's going to be a
fun fantasy adventure, guess again!