Jeff Id writes:

Buffy Minton who provided the email Mime data has produced a spreadsheet of Climategate 1 and 2 emails in chronological order.  This should be an excellent tool to follow conversations through.

Here are the links:

ordered emails – xls (Office 2000, 2003)

ordered emails – xlsx (Office 2007 and later)

Note you can also load these into Open Office and LibreOffice which are both free.