Is there a list of new features that are currently implemented in rails edge?
The changelogs for the various components list changes since the last revision:
http://svn.rubyonrails.org/rails/trunk/activerecord/CHANGELOG
There is the ever helpful Ryan's Scraps - What's New in Edge Rails
http://ryandaigle.com/tags/What’s%20New%20in%20Edge%20Rails
-christos -http://blog.42linesofocode.com