Here’s a brief list of resources for praying the Daily Office and referencing the Book of Common Prayer online.
BookOfCommonPrayer.net
In my opinion, the easiest site to use. Many versions of the Bible available, including the ESV.
The Mission of St. Clare
Pray the Daily Office online.
St. Bede’s Breviary
Pray the Daily Office online – lots of customization available.
The Lectionary
Provides a fantastic calendar view of feast days and readings from the Revised Common Lectionary, along with links to profiles of those being commemorated on any given day.
The Online Book of Common Prayer
1979 American Book of Common Prayer online
The 1662 Book of Common Prayer
Online version of the historic prayerbook
Daily Office Lectionary – ESV
Readings from the Revised Common Lectionary in the English Standard Version of the Bible