PuTTY for Windows saves all sites and configuration in Windows Registry.

Batch file to export sites and configuration from Windows Registry to a .reg file:

@echo off
::
:: export putty sites in ANSI mode
::
regedit /ea "o:\my documents\.ssh\putty-ini.reg" HKEY_CURRENT_USER\Software\SimonTatham\PuTTY

To later import, right-click on putty-ini.reg and select "import" or "merge".