Cookies working on localhost

I wasn't sure whether to post this to the DNS problems or beginners. I am a beginner when it comes to Apache server, so I figured this would be the best place.
I just recently installed Apache server on my Windows XP Pro machine. I'm currently trying to get to a point where I can save cookies form my PHP scripts from my local machine ( localhost ). But as we all know, there are rules to who can save cookies to a client machine. First the domain name has to have two dots...( .domain.com ) This is where my problem lies. .localhost will not suffice. I know i have to change SOMETHING in the .conf files that explains a localhost domain: .pmi.localhost, but I have yet to figure out which commands I need to use to make it so I can save cookies from my local machine TO my local machine. I've tried naming the domain name by machine and the localhost: .machinename.localhost, that didn't work though. Any help would be greatly appreciated.

I'm not sure I understand what you problem is... I've not heard of a 2 dot hostname.... or do you mean there must be:

something.domainname.something ?

Look at the end of your .conf file - mine follows - and add the name to your hosts file too

NameVirtualHost *
<VirtualHost *>
ServerName whatswanted
DocumentRoot "D:\Apache2\htdocs"
</VirtualHost>
<VirtualHost *>
ServerName dev.whatswanted.com
DocumentRoot "D:\Apache2\htdocs\WW"
</VirtualHost>

This mean that if I type in http://whatswanted I see the server root and if I use http://dev.whatswanted.com it redirects to the WW directory and uses that as a virtual root.

Hope this helps