Note on 3.0 beta

docs/topics/3.0-announcement.md

 ## Pre-release notes:
 
-The 3.0 release is now ready for some tentative testing and upgrades for early adopters. You can install the development version directly from GitHub like so:
+The 3.0 release is now in beta and ready for final testing. You can install the development version directly from GitHub like so:
 
-    pip install https://github.com/tomchristie/django-rest-framework/archive/master.zip
+    pip install https://github.com/tomchristie/django-rest-framework/archive/3.0-beta.zip
 
-See the [Version 3.0 GitHub issue](https://github.com/tomchristie/django-rest-framework/pull/1800) for more details on remaining work.
+Currently the only known remaining blockers are documentation issues and tickets. Any critical bugs raised in the next week or two will be resolved for the 3.0 release, but otherwise consider this as code-complete.
+
+Please work through this document throughly in order to understand the API differences that exist between 2.4 and 3.0.
 
 **Your feedback on the upgrade process and 3.0 changes is hugely important!**