Exchange 2007 Beta 2 x64 ENU
http://download.microsoft.com/download/7/1/8/718114a6-c29b-4545-a49c-79dd8c8ad67d/exchange2007-beta2-x64-enu.exe

Exchange 2007 Beta 2 x86 ENU       
http://download.microsoft.com/download/7/1/8/718114a6-c29b-4545-a49c-79dd8c8ad67d/exchange2007-beta2-x86-enu.exe

System Requirements
http://www.microsoft.com/technet/prodtechnol/exchange/2007/productevaluation/sysreqs.mspx

Unified Messaging Language packs (additional)
http://www.microsoft.com/technet/prodtechnol/exchange/2007/productevaluation/sysreqs.mspx

FAQs
http://www.microsoft.com/exchange/preview/faq.mspx

Release notes
http://www.microsoft.com/downloads/details.aspx?familyid=2600CAB1-BF60-49BD-BEF5-CB80083275AD&displaylang=en

Exchange 2007 Management Shell - Introduction
http://www.microsoft.com/downloads/details.aspx?familyid=1DC0F61B-D30F-44A2-882E-12DDD4EE09D2&displaylang=en

Quick Reference for Exchange 2007 Management Shell
http://www.microsoft.com/downloads/details.aspx?familyid=01A441B9-4099-4C0F-B8E0-0831D4A2CA86&displaylang=en

Exchange 2007 Beta 2 Help
http://www.microsoft.com/downloads/details.aspx?familyid=555F5974-9258-475A-B150-0399B133FEDE&displaylang=en

Thinking of installing Exchange 12 CTP build into your production environment?
http://msexchangeteam.com/archive/2006/03/30/423691.aspx

Step by step Setup walkthrough for Exchange 2007 Beta 2
http://msexchangeteam.com/archive/2006/07/24/428424.aspx