Showing other columns along with the Lookup columns
In SharePoint 2007 if you use the Lookup column which will link to another list, we have the option to see only that column. We did not have the option to view the other columns from the parent list in the child list.
In SharePoint 2010 while referring a Lookup column we have the option to select extra columns that needs to shown along with the Lookup column.
Remember that the extra column is read-only which you cannot edit from the Child List.
Here I have a State as Lookup column and enabled AreaCode needs to display along with the Lookup. On Enabling we will have the output like this..