How do i give comment for each Field

Hi,

I need to store some comments/definition for every field in a
table. Is there a way to give comment for the columns while creating the
table itself or after that?

I see something like 'Description' when i want to see the list of
tables/fields in the table using '\d'. Have anyone used this
'Description'?

Any help would be appreciated. Thanx in advance.

bye
Radha