You don't say how old your boys are. If they are 2 year olds my advice would be different than if they were 4 year olds. That aside, most kids outgrow this stage very quickly, especially if the preschool they're attending is staffed by caring people and lots of fun things to do!

It sounds like your boys are experiencing some separation anxiety. That's very common with preschoolers who've not been away from Mom before. But if you don't feel absolutely confident in the school's ability to take care of your boys while you're away then it is possible that your sons are picking up on YOUR separation anxiety. If they see you tense up each morning or if you are overly concerned about their crying at night and pay a lot of attention to their "I don't want to go to school" comments, then the message you may be giving them is "School is NOT a safe place."

But if, on the other hand, you can reassure them that "School is FUN" and that you'll be back for them at 12 o'clock. (Make sure you're there a bit early... never late.)

One other thing... good preschool teachers are compassionate wonderful people and can be very helpful during teary goodbyes. So don't worry... your sons will outgrow this and learn to look forward to their time with friends at school.