OK, crested geckos are pretty easy to take care of, but you really should have done your research BEFORE you brought one (or 2) home.
That said, cresteds are great little lizards and you will probably enjoy them very much. 
There are great care sheets at www.pangeareptile.com, www.acreptiles.com/geckos_crested_basics.htm, and www.crestedlady.com which will give you a thorough grounding in the basics. The Rhacodactylus subforum here, the forums at the Pangea site, and the forums at Repashy's site all have a ton of info on them. Just go on and do a search for whatever you want to learn; most basic stuff is already well-covered and you will get good answers.
If you wound up with two, you probably need to separate them into 2 cages. Young geckos will fight if their size is different, and sometimes even if it's not. 2 males cannot generally be kept together, and if you have a male/female pair, you should definitely separate them if they are under 18 months old.
They will survive for a while on crickets, but when you feed them baby food, it needs to be supplemented with calcium and vitamins, and your crickets should be gutloaded. Keep them hydrated, especially if they are hatchlings or juveniles. I spray my enclosures down twice a day. They drink water from the wet surfaces after spraying. Don't let them get any hotter than 82 degrees for any length of time; it will kill them.
Good luck with your new geckos, and if you have questions that the care sheets don't answer, feel free to ask!