if u want a free domain then get one from http://co.cc/ and after getting it insert it on the box u mentioned and set up the domain with proper name servers(must be mentioned on the registration page) ...
You should join this site which i recommend to everyone ... It is free to join and never have to pay a penny in the future. Refer at least 3 people before launch in April and you will make money. Let's Activate the POWER of WE.
here is my link: http://signup.wazzub.info/?lrRef=61221
I appreciate Zulfiqar Ahsun for this recommendation request. I was asked by someone else and didn't know what I was to recommend. For Zulfiqar's information included in his request for me to recommend his site, I grant that recommendation.