The Text This Week: by Jenee Woodard. The finest lectionary study site on the web. An amazing site which provides links to a wealth of material on each of the lectionary passages, plus many valuable links to general worship, preaching, and biblical studies sites.
Commentary on the Revised Common Lectionary: by Chris Haslam of the Anglican Church of Canada. One of the best introductions to each lectionary reading out there. Offered each week are: Comments - a commentary on the readings for the week; Intros - short introductions to the readings for use in the liturgy; Clippings - more technical information on each reading.
Samuel: (Scripture and Memory UCC Electronic Libary). A resource from the United Church of Christ, which includes lectionary texts, sermon "seeds", teaching and liturgy suggestions