dns setup help

[Salvador Gil]

 I am installing dns server i have a windows nt sbs 4.5 server running
exchanger server ,i have my dsl provider run dns for me but i am setting up
my own i configure my dns server but i don't quite understand how it is
activated on the web do i have to register it with the internic as i heard
off or just let it run and tested also do i have to enter all the computers
in my network using the dns server as host or just leave it the way it is.
In writting the mx record for exchange i had my dsl provider write the
record if i am now using my dns server should i just point exchange to my
tcp/ip address and configure the mx record any response is appreciated
thanks .