Here are some Bible study works that I have found helpful in my study of Psalm 119:
1. Living by the Book by James Montgomery Boice – This is a book developed from the late Dr. Boice’s expository messages through the book of Psalms. The same material is found in the third volume of Boice’s commentary on the psalms.
2. A Guide to the Psalms by W. Graham Scroggie – Helpful introductory material on Psalm 119. Scroggie’s expositions of the psalms are consistently helpful.
3. The Treasury of David (Vol. 3) by Charles Haddon Spurgeon – This is a part of CHS’s classic work on the psalms. A must for any serious expositor.
4. PSalm 119 by Thomas Manton – A three-volume exposition of Psalm 119, with each volume containing more than 500 pages. Enough said.
5. An Exposition of Psalm 119 by Charles Bridges – It contains a sermon for each of the psalm’s twenty-two stanzas and was issued in 1827 when Bridges was only thirty-three years old.
5. Psalms: A Devotional Commentary by Herbert Lockyer, Sr. – A new work I have discovered by the the author of the famous “All” Series (e.g. “All the Miracles of the Bible” and “All the Parables of the Bible”)
7. Trusting Thy Word by Jimmy Draper – Twenty-two expository, homiletical, and practical sermons on Psalm 119
Also I have been greatly helped by the audio of the expository sermons on Psalm 119 by Dr. Steven J. Lawson, pastor of Christ Fellowship Baptist Church in Mobile, AL. You can find them at www.christfellowshipbaptist.org