I dictate SQL using speech recognition, and lining things up is a pain. If I could see where the tab stops are it would save me a lot of time.
Management Studio supports an undocumented feature that Visual Studio has as well. It adds vertical guide lines to the editor window at specific column locations.
Create a .reg file using the text below and open it to merge it with your registry. This will add a line every 8 characters (up to column 96) in SQL Server 2005. Modify as needed to suit your tab size. It does not appear to support more than 12 lines. The RGB portion of the string is supposed to set the color, but it always displays as black for me. You'll quickly notice why this is an undocumented feature - the lines appear in unwanted locations such as the Messages output window.
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Microsoft SQL Server\90\Tools\Shell\Text Editor]
"Guides"="RGB(128,0,0) 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96"