UPDATED 6/4/18: We had a series on the psalms last summer too, but with a very different theme! We've updated the items below with a few additional resources, and took out the ones that were specific to summer 2017.
Someone recently asked for resources in studying the psalms (the focus of our current sermon series), and rather than sending them to one person, we wanted to make it accessible for everyone! I (Brad) am using most of the resources below for sermon prep, but there are a couple others sprinkled in for more general helpfulness too. "Devotionals & Big Picture" are extremely accessible, topical and very application-oriented. The "Commentaries" section include more academically or theologically oriented resources - but still accessible! - if you're looking for a deeper theological engagement (this section is also organized from most accessible to least).
Devotionals & Big Picture
The Songs of Jesus by Tim Keller- An excellent daily devotional that divides all 150 psalms into daily chunks, with a short explanation and a short prayer of response for each one. If you have struggled to keep a discipline of daily reading and/or prayer, this is by far the easiest and most accessible one I've seen (only 1 page of reading per day!).
Praying the Psalms by Redeemer Presbyterian Church (FREE PDF DOWNLOAD) - Intended for small groups of people to work through together, this is an excellent resource that practically walks you through, step by step, on how to pray through the psalms. You will learn a lot along the way, but it's primary purpose is the same as the psalms: to direct our hearts toward God, and have them shaped by Him.
Reflections on the Psalms by C.S. Lewis - Lewis breaks down the major themes of the psalms from the starting point of our every day experience. A few of his conclusions are a little "iffy" (e.g. some of his comments on justice are a bit dated and culturally-confined to 1940's England), but it's classic C.S. Lewis and very reminiscent of Mere Christianity.
Prayer by Tim Keller- One of the best books on prayer ever written. It's based largely (implicitly and explicitly) on the psalms, and describes a practice of prayer that is deeply rooted in the posture modeled in the psalms.
- The Flow of the Psalms by O. Palmer Robertson - A "big picture" commentary that is both deeply exploratory and imminently accessible, his observations and thematic connections are gold printed on paper. While not a verse-by-verse commentary like the other one, Palmer uniquely engages theological and existential implications of the psalter.
- Psalms 1-72 and Psalms 73-150 by Derek Kidner - This is one of the standards for pastors and preachers working through the psalms. It's neither a technical (getting into the finer points of hebrew grammar) nor an expository (easy-to-read preaching summary) commentary, but something in between. If you want robust theology and great historical/cultural context, you can't go wrong here.