Unless your name is something your really really really really don't like. I would probably not try to change the short name. I have seen a number of threads where people have lost their data because they switch the short name.
You can do that if the new account is an Admin account. I cant remember exactly how I changed mine, but it was along those same lines. Create a new account then drag the folders to the new user account.
I must conquer with the others. Unless you really, really, really, really, want to change it just leave it alone.
Don't change your short name. Moving all of your stuff is dead easy - and you don't even have to change permissions on the new user to do it. Just move all of your current folders into the Drop Box of the new user's public folder. Login to the new user, retrieve your stuff, and put the stuff in their respective folderss. Then delete your old user.
Its actualy really easy and i havent had any problems with losing my stuff. go into system preferences and click on accounts. make sure that the lock in the bottom left hand corner is open and ctrl click (the actual ctrl button, not the apple button(not the button)!) the account you want to change your short name in. then click on advanced settings, after that you can change your short name and other stuff. when your done hit ok and restart,
I just got my macbook and in my excitement to get going I made a massive typo in my shortname (I didn't think it would be important, just for 'Hi shortname!' type screens, and thus easily changeable) Imagine my surprise when I saw my home directory.
Anyway, I thought as it was a fresh install I could change it using the method describe above and cause very little damage as I had no documents on there.
Is it likely to cause any problems in the future, though? My old home directory is still there, is it safe to delete this? Or should I go through the new user account method to be sure. If I do do this, and delete my old account, will it remove any programs off the hard disk or will they be 'ghost installs' forever?
I'm coming from windows so my mac logic isn't quite what it should be, so please forgive me if these are stupid questions!