If they came to me, as I am right now, my advice would not be anything that they would want to hear. I'm a teacher, parent, and a high school coach. I would definitely tell Pony and Johnny that they should go to the police and explain exactly what happened. Running away and hiding makes them look guilty. Ponyboy and Johnny can claim legitimate self defense, and likely face little to no charges. Additionally, they are minors, so their punishment would not be as severe.
Of course, if I was a fellow Greaser, I would likely try and help them avoid being caught at all. I wouldn't want them found in my house, so I wouldn't offer them a place to stay. I would give them food and money, and I would probably offer to drive them to some kind of hideout location until everything calmed down. I guess I wouldn't act that much differently than Dally does.