Mystcraft build for 1.4.6 is up and ready! :)
Sorry for the general delay. Many thanks to cpw

This is primarily an update release.
Note that this does NOT contain the celestial mechanics or other thing which were streamed earlier. Check out the change log for what it DOES contain. :P
Mostly this contains bug fixes. A few minor interaction changes, such as shift-click removal on stands and interacting with the receptacle.

To recap: there is only one download (found at the bottom of this post); This file is the universal install for client and server; it no longer goes in the jar.
Mystcraft now goes in the mods folder.

Download: [1.4.6] Mystcraft Universal
Check the Mystcraft Forums for updates and the change log.