i don't have one recipe that i follow. just usually throw this into a blender and go from there:

frozen fruit (whatever i have on hand) about a cup
a banana if i can find one (quite rare lately)
a small thing of yogurt (whatever i have on hand)
some milk
and a small bit of ice cream (makes it really smooth and oh so good!)

i like the ones that are posted on here. makes me want to go home and make one.