How to make a Hidden Tor Bitcoin Mixing Service?
BitcoinFog is popular and has been around for a few years. If you really want to make your own, you'd need a dedicated server, Tor (for the hidden service), web server software like Apache, and Bitcoin-Qt (or some other bitcoin software which can be interfaced with through PHP). To have it be really safe, you'd need to set in place other precautions like a firewall or a separate server running Bitcoin-Qt.