I like Scarleteen.com, but it really doesn't matter as long as you don't just point her at the Web and tell her to go look up "anal + teen," OK?
Let the professionals handle the "does it hurt?" and "will I like it?"-type questions, but as her dad you don't get to shirk the harder parts, where you ask her what she's heard, how she feels about it, whether her friends are pressuring her, and what she will do if they do pressure her. I would hope you've already talked to her about respecting herself and her body and not doing anything until or unless she really wants to, and then only once she's educated herself about risks and how to avoid them. If you haven't, well, for God's sake, man, she's 14. She has all kinds of excuses for stupid and irresponsible behavior. What's yours?