Here is a handy little script for running in Management Studio or the like:
USE [databasename]
DECLARE @theobj SYSNAME
SET @theobj = '[schemaname].[objectname]'
EXEC sp_help @theobj
EXEC sp_helptext @theobj
Just replace the names in square brackets with what you are interested in but don't remove the square brackets. Note that the last line sp_helptext only works with code based objects like stored procedures and not tables.