Just found this up on the Forefront blog http://blogs.technet.com/fss/archive/2008/08/11/forefront-for-exchange-sp1-rollup-3-has-been-released.aspx
Forefront for Exchange SP1 Rollup3 has been released. The fixes that are included with in Forefront for Exchange SP1 Rollup3 are as follows.
Prior to full publication of Forefront for Exchange SP1 Rollup3 we are making our customers aware that this release of Forefront for Exchange is now available. Please Contact Microsoft support if you would like to install Rollup 3 for Forefront.
Interesting that it is NOT actually released yet!