I've had several questions recently about how to index Exchange Server 2007 Public Folders with SharePoint Server 2007.
Unfortunately with the RTM versions of both products it's not actually possible due a couple of issues with both Exchange Server 2007 and SharePoint Server 2007.
The good news however, is that everything is back in working order if you install Exchange Server 2007 Service Pack 1 *and* your SharePoint Server also has Service Pack 1 installed.
The RTM versions of Search Server 2008 and Search Server 2008 Express are unaffected (As they already include the Service Pack 1 changes), so providing Exchange Server 2007 has Service Pack 1 installed they will both work.
None of this affects Exchange Server 2003 which works with the RTM versions SharePoint Server 2007, Search Server 2008 and Search Server 2008 Express and SharePoint Server 2007 with SP1.
Hopefully this stops people scratching their heads...
Senior Technical Product Manager