This is from: http://technicaldoc.blogspot.com/2007/03/export-putty-settings.html
To export PuTTY settings:
Open the registry with Start Menu -> Run -> regedit
Go to "HKEY_CURRENT_USER\Software\SimonTatham"
Right-click SimonTatham and choose Export
To import PuTTY settings:
- copy the file to a new machine
- right-click on the file and choose "Merge"