Development/Beta stream builds of Swing Designer are now available from the following update sites...
Eclipse 3.7:
http://dl.google.com/eclipse/inst/d2wbpro/beta/3.7
Eclipse 3.6:
http://dl.google.com/eclipse/inst/d2wbpro/beta/3.6
Eclipse 3.5:
http://dl.google.com/eclipse/inst/d2wbpro/beta/3.5
Eclipse 3.4:
http://dl.google.com/eclipse/inst/d2wbpro/beta/3.4