Suggestions on how to make DNS changes?

[Bradley Miller]

Ok, as I mentioned earlier, I now have two database servers.   Right now
I'm referring to them by IP address, but I want to put them in as DNS
entries so I can have db1.something.com and db2.something.com.  Then if db1
goes down, I can do a dns change and suddenly db1 is the ip of db2
(flip-flopping from master to slave).  Someone mentioned nsupdate . . . .
could someone give me a little pointer or two on how that works, or what
the best method would be for what I'm wanting to do?

Thanks!

-- Bradley Miller