I had my coffee this morning at Starbucks. The store is about 2 miles away from my house. I had a hot cappuccino to start-up my day and picked up the "Song Pick of the Week" card at the store. The card has a 12 digit download code provided at the back of the card, you need this to redeem your free song.
There are instructions printed on the card to download from PC or Mac, and if you prefer to download content on your iPhone, iPad or iPad touch, just follow the step by step procedure included on it as well.
The code provided has expiration date, so, make sure to check the date before you proceed.
You can also redeem the code in-store. Drop by any Starbucks location near you, connect to their wi-fi and go to http://starbucks.yahoo.com.