In SQL server management studio there are a lot of shortcuts and one of the new shortcuts in SQL server 2008 is the shortcut for selecting text by columns in the query editor window. Lets say you want to change the alias for a table you need to change all the columns that is using the table alias. All you do is place the cursor where you want to start the selection and hold the SHIFT + ALT keys while you use the arrow keys to expand the selection like the image below.
If you want to use the mouse, you hold the ALT key and drag the mouse to expand the selection.
If you are using SQL server 2012 you can actually replace the selection by entering a new text and all rows will get the new text.