Sam's Blog

      SPSite site = SPContext.Current.Site;    

      SPWeb srcSite = site.AllWebs["Site_Name"];    

      SPList list = srcSite.Lists["Announcements"];    

      SPListltem litltem = list.items[5];    

      SPAttachmentCollection attachments = listltem.Attachments;    

      string fileName = file.Name;    

      byte[] binFile = file.OpenBinary();    

      attachments.Add(fileName,binFile);    

      listlitem.Update();