Am I wrong to assume that you used Address book.
If you use Address Book all the Data should be stored in:
HD > USERS > "Your User" > Library > Application Support > Address Book > Meta Data:
That should be a contact card for address book for every person in it.
Let me know if that works for you.
Or sign in for MobileMe (free trial, 60 days) and use it synchronization function. It also allows you to transfer e-mails.
Apple has provided a way to do this without signing up for anything. On Tiger's address book, go to File->Backup Address Book. Copy this file over to your new mac and in Leopard's address book go to File->Import->Address book archive.
Apple has provided a way to do this without signing up for anything. On Tiger's address book, go to File->Backup Address Book. Copy this file over to your new mac and in Leopard's address book go to File->Import->Address book archive.