The stores feature "Powermat Spots," which are designated (and literal) spots on tables and counters where customers can place their compatible devices to charge them wirelessly without any need to take up an outlet.
In case your phone isn't capable of wireless charging, the Starbucks stores are offering Duracell Powermat "rings" for loan or purchase. The rings plug into your phone and give it the ability to charge wirelessly. They can be purchased in-store for $9.99.
You can find the nearest wireless charging-enabled store at www.powermat.com.