Here are some links to some sources of good (and free!) sermons to download.
Sermons from particular churches…
All Souls, London
Aisquith Presbyterian Church – Dale Ralph Davis
Bush Hill Park Community Church
Capitol Hill Baptist Church – including Mark Dever’s excellent overview of the Bible – one sermon per book!
Christ Church Cambridge
City Evangelical Church
Co-Mission Churches in London
Enfield Evangelical Free Church
Farnham Baptist Church
Grace Community Church, Bedford
Mars Hill Church
Redeemer Presbyterian Church – Tim Keller
St Andrew the Great, Cambridge
St Ebbes, Oxford
St Helens Audio
Sermons and resources from John Piper
Woodland Presbyterian Church – Dale Ralph Davis
Collections of Sermons
Bible Bulletin Board – a massive selection of sermons from John McArthur, CH Spurgeon, Jonathan Edwards, JC Ryle etc.
Biblical Theology Briefings – a preaching web workshop for pastors committed to Biblical Exposition.
Blue Letter Bible – audio Bibles, Commentaries etc.
ProcTrust resources – sermons from Dick Lucas, David Jackman, Tim Keller, etc. etc.
Sermons from Evangelical Movement of Wales – Ian Hamilton, Philip Swann, Edward Donnelly etc.