How to Join LinkedIn without an Invitation
Click the blue Create My Profile button to continue.
LinkedIn offers to import your contacts from your e-mail program. If you see your e-mail system among the choices, you can pick the radio button next to that system and then click the Login button. LinkedIn will walk you through the steps of importing your address book and offering you the chance to connect to existing members of LinkedIn. You can also do this after account creation by clicking the Skip This Step link.