Exchange 2007 documentation is availabe on Microsoft Technet site
Hello,
There are a bunch of information about Exchange 2007 on Technet website, right now it isn't a full documentation but may be a start point of Exchange 2007 help files: http://www.microsoft.com/technet/prodtechnol/exchange/E2k7Help/457de3d0-ae83-4c45-899f-426891685ee5.mspx?mfr=true
Regards,
Anderson Patricio
http://www.andersonpatricio.org