Apologies but one more newbie question.
I don't have either of the above.
Is this because I need to load from the CD which I can't as a Mac user?

1) Do you have a Blackberry Data Plan? If not no dice. If yes try #2 and #3
2) Login into your BIS login page and resend service books
3) Options---Advanced Options-->Host Routing Table-->Register Now
4) After #2 and #3 pop the battery out(hard reset) wait 30 secs.....pop back in.

Ditto Moosehead, being a MAC user has nothing to do with how your BB operates.

I presume therefore I can't access my home network, using that to access the internet through the BB?

I say you presume correctly. You will have to use the internet data plan on your blackbberry to get out to the internet once you get the service books registered on your blackberry device using the above method in response #2

The blackberry 8700 can not navigate your personal files on the network.

Or was your question in regards to using your 8700 as a modem for your computer/laptop...
If I misread your question please restate it.

Thanks.