We have to start daycare for my 2-year-old son next week, and we're in the same boat. In the past, when we've left him with friends, he has literally cried the entire time he was there. Once he cried so hard he made himself vomit. I think it may be a little easier on him right now, but I'm still nervous.
My mom just bought us a book called "The Kissing Hand" for him - it's about a little raccoon that is afraid to start school. The mama raccoon tells him the secret of the "kissing hand" which is that if she kisses his hand, he can put his had to his cheek and think "Mommy loves me" all day. It comes with little heart shaped stickers. I read it to my son this morning for the first time, and he liked it. So that may make things easier for him. I'm going to read it to him in the mornings this week, and give him a sticker each day, so that when he starts daycare he'll know the story and will feel better about it.