Exchange 2007 System Requirements (note: Page File should be RAM + 10 MB):
http://technet.microsoft.com/en-us/library/aa996719.aspx
Memory Requirements (note: minimum memory / # of storage groups):
http://technet.microsoft.com/en-us/library/bb738124(EXCHG.80).aspx
Steps to mitigate excessive paging:
http://blogs.technet.com/mikelag/archive/2008/10/17/steps-to-help-mitigate-excessive-paging-and-working-set-trimming-issues.aspx
