The SysProperties Table has the description.

the name should be 'MS_Description'

Here I have a sample code

select O.Name [Table_name], c.name [Column_Name],

p.Value [description]

From dbo.SysObjects O,

dbo.SysColumns C Left Outer Join

(select id, smallid, name, Value from dbo.SysProperties

Where Name = 'MS_Description') P

On P.id = c.id and P.smallid = C.Colid

Where O.id = C.id and ObjectProperty(O.id, 'ISUSERTABLE')=1

Order By O.name, c.colid

If you have different users owning tables with same file names You may have to add the table_schema too.