PuTTY itself does not provide a means to export the list of sessions, nor a way to import the sessions from another computer. However, it is not so difficult, once you know that PuTTY stores the session information in the Windows Registry.
To export the Putty sessions, run:
regedit /e "%userprofile%\desktop\putty-sessions.reg" HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\SessionsOr, to export just all settings (and not only the sessions, run:
regedit /e "%userprofile%\desktop\putty.reg" HKEY_CURRENT_USER\Software\SimonTathamThis will create either a putty-sessions.reg or putty.reg file on your Windows dekstop. You can transfer these files over to another computer, and after installing PuTTY on the other computer, simply double-click on the reg file, to have the Windows Registry entries added. Then, if you start up PuTTY, all the sessions information should be there.