Aliased Column name in SQL Server
As @JNK mentioned, you can use a view.  There are some steps to take, of course.  The view should map only to columns in a single table. 

I assume that you do not want to deploy completely updated code that uses the new name.  So, you can create a view with a different (but similar) name and any new code could use the view, and the new name. Existing code would still be going directly to the table. 

This would get you moving, but one day you will probably want everthing to use the new column name.  Eventually, you will have to deploy new code.  Which would still mean a number of name changes if you don't want to have the view layer over the table.