Readings
The Transcendence of Allah - Refuting Doubts and Misconceptions - Dr. Saleh as-Saleh
Where is Allah? - Statements of the Salaf - Imaam Bukharee
Where is Allah? - Ibn Abdul Barr on the Meaning of Istiwaa
This one nicely lists Quraanic proofs in bullet form for quick reference
Allah is NOT in the midst of, or surrounded by the heavens BUT He is above the heavens
