My best friend called my boyfriend?

Hmmm...I would be interested to know how she got the number....did you give him his number, or did she ask him for it, or did he volunteer the number to her? Now, the question to you is----if this person doesn't care about anybody, then why is she your best friend? If anything, maybe you need to get better 'best' friends. Even if you confront her or be mean about anything, is not like she is going to stop her behaviors, because as you clearly said, she doesn't care about herself or anyone....

Well, your kinda in a hard spot. It all depends on if you value your friendship with her. what I mean is if you ask whats going on she may be set back due to the level of trust you show her. Was she friends with your "Boy friend" before? Did she tell you she called? Did he tell you she called? If he did but she did not then you might have nothing to worry about. If they both did not come straight out and tell you and it just pop up in a conversation...say 3 weeks later. Then you might want to react a bit but tread lightly. Why? Some guys like a jealous women because it shows that they care. Then again some do not. My best advice is think about what you want to say. If and when you bring it up to both or one of them, spin it around and ask them what they would think if you were to call his friend/or her boy friend.

Just be careful...because you could come out to seem like a Bitch.

So she called him on the phone? I don't really see the issue. She called him, not drove over to where he's staying and had hot crazy sex with him. I suggest you chill. :p

If your best friend called your boyfriend, she isn't a friend at all. Stop the relationship with her immediately and let her know she crossed the line. With "friends" like that, you don't need enemies!