In August it looked like a Compiz 0.9 beta was coming (this is coming after the last Compiz release was in February of 2009), but it never quite made it there. Compiz 0.9 was then planned for release by the end of 2009, but it never made it and no revised release schedule came about.
Nearly four months into 2010, it looks like the Compiz 0.9.0 unstable release may finally be set to arrive. Sam Spilsbury has written on the Compiz mailing list that a huge milestone has been hit and that's the last plug-in has been ported to the new Compiz code-base and it's now working. This last plug-in to be ported is Dbus. There's still some bugs left, but it seems to be in pretty good shape.
Now that the plug-ins have been ported over for Compiz 0.9, a release is in sight. A release announcement is already being drafted, but there still are a few TODO items left:
1. The initial stacking bug has come back again :(
2. Bug with GTK Window Decorator where reloading the decor plugin will cause it to fail
3. Windows disappearing when they change their title / size. I think this was introduced only recently, so I can probably bisect to find out what caused it and revert that commit.
Hopefully we will finally see Compiz 0.9, which marks effectively a complete rewrite of this project, in April!