See the blog post over at Oracle for details, and be sure to send Christopher Jones an email (via the address in his post) stating you're an active user of the client. As Christopher mentions in his post,
You can really help us justify resources for the OS X bundle if you email me letting me know you are a fan. Since Instant Client is a free download, it is tricky for us to know how widely it gets used.
Jump to OTN to download, but please remember to email Christopher as well, if you're interested in seeing the client for future releases.