<p>Has Java 1.6 SDK been released for mac? I can't seem to find it...</p>

Yes, but only for 64-bit Intel-based Macs, i.e. Macs using Core 2 (duo or solo) or Xeon chips. The original Core chip is not supported, nor is any PPC chip. Also, Java 6 is currently Leopard-only. The update should appear in Software Update, if you have a compatible Mac and recent-enough OS version.
Here are the release notes for the
first update
. And here are the
second update
's release notes.