Sites with everything you need for saying the Office
http://prayer.forwardmovement.org
A site with BCP language and traditional chants
Sites about plainchant
http://www.ccwatershed.org/Gregorian
http://www.gregorien.info/psalm/all_tones/en
http://media.musicasacra.com/weber/various/chanting%20the%20psalms%2009.pdf