How to implement and use BIP 70? I have a server running bitcoind 9.x, how can I incorporate features such as return addresses to my customers using BIP 70? I have seen the GIT repo but is it something that I have to download or is it already implemented in the bitcoind daemon I'm running?

Thanks
It's neither part of the Bitcoin daemon nor something you can just download. It's code you are expected to write and integrate with your web commerce application. The code in the git repository is only a sample.

See my answer  https://bitcoin.stackexchange.com/a/24450/5757 for some further information.