Go to the keyclone website (http://www.solidice.com/keyclone/index.html) and download the latest version (keyclone v1.9i 24jul2009a)
Alternatively you can click the Keyclone software link up above on this website.

Once installed, start it normaly and if you license is dead it will prompt you with "Get license / Transfer / Re-check" buttons.
Hit the "Transfer" button, enter the email of the account you bought keyclone with and follow the instructions. it should transfer your licence to the machine you are currently using.

Edit: Seems like i need to type faster, Khat beat me to it.