When I wash my spinach, I like to wash it and then soak it to make sure that I didn't miss any dirt, grass, bugs...etc. Then I rinse it one more time. After I rinse it, I put it in freezer bags and try to squeeze out as much air as I can.
I love having a freezer full of spinach for fruit shakes/smoothies, I bet I've got 30+ bags. We have started putting spinach in ALL of our morning smoothies. The frozen spinach works great, you can use the entire bag, or break-off what you want to use and put the rest back in the freezer. It is also great because it breaks up easily, so you don't have one big clump of spinach you are trying to blend....and because we grew it....we know that it is all organic!!