After a lot of thought about this blog post, I have decided to retract it. I had heard lots of rumors that bottling butter was not safe, and figured that there was just a little paranoia going around. However, after reading this notice, I have decided that I don't think I will be bottling butter in the future. I don't think that there is any scientific evidence that bottled butter can cause botulism, but there also isn't any evidence to support it as a safe procedure.
If you would still like instructions for bottling butter, it can be found here. I advise you to use your own best judgment when deciding if this is a storage option for your family. And as always, if you feel uncomfortable about a storage method, don't do it and find an alternative instead.