Any fruit that doesn't have a skin (like bananas, apples, peaches), just wash first. For berries and bananas, we put a piece of wax paper on a cookie sheet or stiff cutting board and lay the fruit out on it (bananas we cut up in 1 inch circles). Freeze till firm, remove from wax paper (I use the wax paper because it normally allows a easier release than if you just put it straight on the board or cookie sheet). Then place in a freezer bag with as much air removed as possible. Put in the back of the freezer until ready to use.
Some fruits (peaches & nectarines come to mind) need to be blanched and peeled (you don't want the skin anyway, since unless you're getting organic, it's probably got a lot of pesticides on it-bleh).
Cherries, you can wash, pit with a small knife and freeze on wax paper.