changing localhost name

[AuntieParticle <AuntieParticle@xxxxxxxxxxx>]

I am wanting to change the localhost name on my system. I have looked 
through the archives and have found a few messages that are related to 
this but I want to make sure I understand it completely before I proceed 
since I am fairly new to linux. As I understand it I should *add* a line 
to etc/hosts like:

127.0.0.1        nameiwant.localdomain nameiwant

but leave the line:

127.0.0.1        localhost.localdomain localhost

Just as it is.

So that it will looks something like this:

127.0.0.1        localhost.localdomain localhost
127.0.0.1        nameiwant.localdomain nameiwant

Then in etc/sysconfig/network I should *change*

HOSTNAME=localhost.localdomain

to

HOSTNAME=nameiwant.localdomain

Is this correct? Am I missing anything else that needs to be changed? 
For example will anything else need to be changed for sendmail?

Thanks,
AP