How do I find out what type of plants/trees I have growing my garden?

I just bought a house and I am wondering what these smaller trees are called? The past owners planted a bunch of everything mixed among each other. I know that next to a shrub, I have a chive plant growing on one side. But, how do I find out what these trees are called? I have one of each side of the house, and I'm just curious. Is there any site or anything? I'll take some pictures in the morning to anyone that might have an idea, my e-mail is: ashleyheeter@gmail.com