Don’t. Really, don’t.
The Title field is the only exposed site column in the Item content type. Pretty much every single list item across the board inherits from this content type. Therefore, when you change the name of the title field, you’re changing it for all lists in the site collection.
The problem is, that there’s no warning that that’s about to happen, and if you start from a list, you may be under the impression that you’re only changing it in that list.
Pretty much not cool.
So let’s say that you do change it. You can just change it back, right? Wrong. The Word “Title” is a reserved name in SharePoint and you can’t use it in a field name. There’s no way in the UI to change it back.
However, you can do it through the object model (API) by writing code, or using a Powershell script (get used to Power Shell everybody…). Thanks to the From the Field Blog for this highly useful Powershell script:
$fld = $web.Fields.getFieldByInternalName(“Title”)?
$fld.Title = “Title”?
$fld.PushChangesToLists = $true?
And yes, I’ve had to use it!