Umm, first get a new email address from a provider like yahoo, gmail, hotmail, etc. Then edit your iTunes Account by going to the iTunes Store/Click on your user name in the top right of the store window/Click View Account in Login Window that appears/Edit Account Info
By creating a new user with the short name you like, as the name of the Home folder is derived from the username you chose. Thus the name of your Home folder is static and shouldn't be changed.
Have you used MRoogle yet to search for similar topics?