Quick and simple script needed

I need to create a cgi script using Perl that basically loads a web page,
asks for a Username and stores it in a variable "Username".  Also, it takes
the domain name of the site (that runs the script) and stores that in the
"Domain" variable.

Next it needs to do a substitution:

http://www.anothersite.com/whatever...ame&var2=Domain

And redirects the user to that url.

Overview of why I need this:
I do free hosting for some customers and they have addresses in the form of
http://username.domain.com.  I have a billing system but it was made for
pure domain names, and not subdomains.  Therefore I need to gather
information from the user, as well as the site calling the cgi, to form this
domain name part, which ends up being http://username.domain.com.

Please reply with your email address if interested, or contact me at
x-redb-aro--n-x@hotmail.com (remove all of the dashes).