Security concerns on IP addressing

[M S Szeto <"ims02 @ netvigator . com"@netvigator.com>]

Dear all,

Does anybody know if my private network is going to be connected
to the Internet, what are the most appropriate approach relating to 
network security on using the IP addressing scheme on my private
network?

If I follow the RFC1918, what are the benefit? Is a firewall
still be necessary connected between my private network and Internet?

Many thanks.