Don't let him cry it out this young unless you make sure he's not hungry first. Some babies can make it through by 3 months, but not all. Be sure to feed him more all day long for a few days so you know he's satisfied at night, and when he first wakes, I would feed him if he hasn't eaten in a few hours, but THEN I would let him cry to get used to his crib.
Also, start having him nap there during the day. He's used to a lot of stuff in the day that soothes him-noise, swinging, etc, and he's just not used to the quiet crib at night yet. Don't let him train you to do all sorts of stuff at night, just let him get used to it. See if there is any other comfortable simulation you can do in the crib, or you could let him sleep in the pack and play.
My 5 month old was the first of 3 not to love her crib, but I noticed whenever I set her down on our down comforter on the bed (when she was a couple months old) and she "sunk into it" she would fall asleep or lay there happily. We started putting a doubled up down comforter under her in her crib and she's loved it ever since. We also feed her constantly in the daytime, because this got my other two sleeping through by 3 months. She started sleeping through by 3 1/2, 4 months. Good luck!