I see this all the time but i dont know if they use a loop or no.
They actually use a combination of two BodyForce objects.
You can use a BodyPosition force to hold the object up. Here is more information on that: http://wiki.roblox.com/index.php?title=RBX.lua.BodyPosition_(Object)
Then, you can use BodyAngularVelocity to rotate it. More information on that: http://wiki.roblox.com/index.php?title=RBX.lua.BodyAngularVelocity_(Object)
I recommend going to the wiki if you want to Learn how to make one. This for help on how to fix or make a script work correctly and more.
There is a twitter account made by Merely called @RbxDevTips that has a picture of BodyForce objects. You can view it here: http://t.co/9a1yN0Dx4p