Short name?

Read this:

http://Gnarlodious.com/Computer/MacOsx/ChangeUsername

You can use this tool to change your account's short name.

(20160)

If you choose not to preserve user and network data, you will need to recreate the accounts afterwards, and the newly created accounts can have different short names. Otherwise, the files containing the previous short name will be preserved, and it needs to be changed in another way.

(20267)

The short name is the same name of your home folder. The name that show's up at the login window is the Name, this can be changed by going into the Account Preferances in System Preferances.

The previous link on how to change the home folder and short name using NetInfo Manager is the easiest way to change both. Apple has also released a more complex article on how to change both of these items.

Mac OS X: How to change user short name or home directory name
http://docs.info.apple.com/article.html?artnum=106824

If all you want to do is change the home folder name you can rename the home folder (lower case and no spaces), create a new user account with the same password and the short name should be the same spelling and caseing of the renamed home folder.

Yes. Log in with the new user account, and then copy the old account's home folder to the desktop of the current account; you will probably need to authenticate yourself. Next, go through that folder and move the items you want to transfer to the corresponding locations inside your current home folder.

(20285)

you'll end up running into owner ship permissions, to get around this you could go into terminal and enter:
sudo -s <return>
chown -R <new short name> /Users/<name of home folder> <return>

but once again i would recemend the steps given in the above link using NetInfo Manager