How can I retrieve my address book?

Question

I lost my mobile phone on Friday, which isn't the end of the world. Except it is.
I have about 300 names and addresses in the phone book and I'd like to get them back. I remember making a back-up on my computer last year when I got a new handset (it's a mac running os x) so I should in theory have a file somewhere, but I have no idea what the file will be called or where it could be.

Any ideas?

Note: The phone was a Nokia 6230i

Answer 1

2 possibilities!

1 it's all inside the "address book" program from apple. You sync'ed it with the built in sync program.
2 you installed a program from your ISP or nokia (not likely)

just run "address book", you can re-sync your new phone with the old data!