Awe sad day-you probably thought-they're both so stinking cute how could I only take one home. ~hugs~ You've got a long road ahead of you-but you can do it if you're committed. Do you think you're up for the challenge?
Some of the basics-What do you know about their history/lineage (Pit Bulls in general-not specifically your dogs)? Are you aware of the difference between DA/AA (dog aggression or animal aggression) versus HA (human aggression)? If not, in this breed DA/AA is common and accepted as a typical breed trait. HA does happen from time to time (the breeds that fall under the PB umbrella have been overbred and crossed with bad bloodlines way way too much recently) but it is highly frowned upon and most people would encourage you to euthanize a dog that showed severe signs of it. Are you aware of the different breeds that fall under the Pit Bull umbrella?-APBT, SBT, Amstaff and Ambully. Sometimes there are others based on their looks or other people's ignorance, but typically these are the most common.
Crate and rotate will be your best friend! For me, at first-I was against it. I was against crating. But I really didn't know any better. I thought it was doggy jail. I then realized my dog was much more comfortable/less stressed in a kennel. He loved it-and mostly slept. There are things you can to do make crate training positive for your pups. They're going to need to be crated separately for safety reasons. We've gotten to a point in our house where we rarely use crates, but we still use the crate and rotate method. When we leave the house, one of my dogs stays in my bedroom while the other has access to the majority of the remaining house (we also have cats that we put in a room when we're away). When we're home our dogs are separated by baby gates.
You're going to have to make time to train separately. Personally I'm not against training your dogs at the same time for some things. Sometimes if one of my dogs has a trick/task down to a "t" but my other dog isn't getting it. If I ask the dog that's good at it to perform in front of the one that isn't getting it, it seems to get the gears moving in the dog's brain who's having a tougher time with it. But you run the risk of this thing...that I can't remember what it's called (maybe it's in the link provided above) but basically the dogs form a stronger bond with each other instead of each of them forming a strong bond with you. Since your dogs are already starting to fight-that may not be the case, but it also means you may not be able to train them together.
You're likely going to want to look into dog aggressiveness versus dog reactiveness. And you need to know (as I hinted at early) it's not a fault, it's something PB owners commonly deal with-so that means you're not going to be able to train it out of your dogs (if it turns out they have this trait). BUT! (there's still hope) you can train your dogs to be behaved. Not act like bungholes. To look to you for direction when in an uncomfortable situation. And you as the owner can set your dogs up for success (instead of failure).
Please stick around and do as much research as you can. This is a great forum with tons of very informative people and a lot of resources available to you. If you feel that you can not committ the amount of time and dedication that is needed for both of these pups it would be in everyone's best interest (yours and the dogs) to find a new home for one (or both-whatever you decide) immediately. It's easy to place puppies...the older they get-the harder it is.
I suggest spaying/neutering as soon as your vet is comfortable with it. I also suggest getting into some obedience classes so you have a foundation with them. And I strongly suggest staying far away from anything remotely related to Cesar Millan or anyone that teaches like him (dominance, alpha, pack leader, etc).
Here are a couple of websites with some more information. Please be sure to ask your questions (all of them, even if you think they're dumb-we'd rather answer something for the 1000th time than the alternative).
http://www.badrap.org" onclick="window.open(this.href);return false;
http://www.pbrc.net" onclick="window.open(this.href);return false;
http://drsophiayin.com/resources" onclick="window.open(this.href);return false;