Ideally connecting to an ISP for broadband internet should be Operating System agnostic. Neither should it matter what specific computing device is connected through the ethernet interface. As long as your computing device (Apple Macbook in this case) has the right software drivers for your ethernet interface and you are running a standard DHCP client and other network client software services required, etc.
Arent there ISPs in Nigeria that provide a connection using the standard ethernet interface?. i.e something of this sorrt :-
Your PCs Ethernet interace <--->Ethernet port on rf/cable modem<-->RF/Cable Interface on radio/cable Modem<-->ISPs Servers
I know IPNX provides such a connection.
Perhaps there are other knowledgable folks who can pitch in?.
peace
Brume
PS: You may find some interesting information in the following thread/posts :-
http://www.nairaland.com/nigeria/topic-67946.0.htmlhttp://www.nairaland.com/nigeria/topic-67946.0.html#msg1328503http://www.nairaland.com/nigeria/topic-67946.0.html#msg1328791