I know there is a service in SBS 2008 R2 for Exchange Replication, but I can not find any documentation of the requirements to successfully set this up.What can it replicate with?

There still is no SBS 2008 R2, not even an SBS 2008 with Windows 2008 SP2 and Exchange Server 2007 SP2 - you have to do the upgrade manually. SBS 2008 supports the same features for Exchange high availability as the Exchange 2007 SP1 Standard Edition: Local Continuous Replication (LCR) and Standby Cluster Replication (SCR). A a rule of thumb LCR requires 1 additional GB of RAM; additional processing cost is approximately 20 percent, and you should place your passive storage groups on storage that is isolated from the active copies of your LCR-enabled storage groups (different disks and controller). SCR requires an additional Windows 2008 Server with Exchange 2007. Windows Small Business Server 2008 Technical FAQhttp://technet.microsoft.com/en-us/sbs/cc817589.aspx LCR is the more common option in the SBS world. The two links below (while not specific for SBS 2008) should give a good idea about LCR: Senior Microsoft technical writer Scott Schnoll: Local Continuous Replication in Exchange 2007 (video 21:58)http://msexchangeteam.com/videos/9/drandha/entry427787.aspx Demystifying the Local Continuous Replication (LCR) featurehttp://www.msexchange.org/tutorials/Demystifying-Local-Continuous-Replication-LCR.html SCRManaging Standby Continuous Replicationhttp://www.msexchange.org/articles_tutorials/exchange-server-2007/high-availability-recovery/managing-standby-continuous-replication-part1.html Standby Continuous Replicationhttp://technet.microsoft.com/en-us/library/bb676502%28EXCHG.80%29.aspx Exchange Server 2007 High Availability Storage Considerationshttp://msexchangeteam.com/archive/2006/10/05/429103.aspx One thing common: SBS 2008 Backup is not designed to work with either LCR or SCR. The backup job will not fail, however you will receive an error under the details of the completed job telling you that Exchange is not available for recovery. Likewise, when you choose to restore an application from your backup job, you will not see Exchange in the list. This prevents you from performing an online backup or restore of your Exchange data.SBS 2008 Will Not Perform an Online Backup of Exchange if LCR or SCR is Enabledhttp://blogs.technet.com/sbs/archive/2009/02/23/sbs-2008-will-not-perform-an-online-backup-of-exchange-if-lcr-or-scr-is-enabled.aspx MCTS: Messaging | MCSE: S+M | Small Business Specialist