Programmatically Upload file in Document Library

Following links explain how to uplaod file(s) into a sharepoint document library

• http://wss.collutions.com/Lists/FAQ/DispForm.aspx?ID=190
• http://philwicklund.com/archive/2008/04/02/programmatically-uploading-a-document-into-a-document-library-with-meta-data-modifications.aspx
• http://nishantrana.wordpress.com/2008/06/26/programmatically-uploading-and-setting-permission-to-a-document-in-a-document-library-in-sharepoint/