Many popular text editors such as UltraEdit, SlickEdit, NEdit, etc., support text manipulation of columns such as selecting a column and cut/copy/paste operations on a column. As of version 3.2, Eclipse does not support these column based editing capabilities. (See this eclipse bug report) From the bug report, it looks like a patch was created on 1/29/2007 and this feature may be implemented in Eclipse version 3.3.
However, there is a plugin called Columns for Eclipse, which implements this functionality. I installed it, and it seems to work well. Note, this plugin didn't work with Java version 1.4.2. If you use this version, the icons and menu will install nicely, but you will get the error message: "The chosen operation is not currently available" when trying to use a feature. I installed Java 1.5 from http://www.java.com/en/download/manual.jsp and everything worked great after that.