The Starwood Preferred Guest Program is a free loyalty program, not a credit card. They do offer one in partnership with American Express, but it's not required to partake in the program.
Basically, you earn points each time you stay at one of the hotel chains in the Starwood group: Westin (the Swan), Sheraton (the Dolphin), St. Regis, W, Aloft, Le Meridien, Four Points, Element. Points are also earned for meals and services utilized during your stay. The points can then be used for free hotel nights, upgrades or for a Cash + Points stay. For example, for my upcoming stay at the Swan, I'm paying $75 and using 5,000 of my Starwood points, per night.
Also, if you are a AAA member, you can join the Starwood program through AAA, which gives you Preferred Plus status right off the bat, and makes you eligible for a room category upgrade (upon availability). Nothing is ever guaranteed, but I've been upgraded each time I've stayed at the Swan or Dolphin. It's a really nice perk.
As far a recommendations for room location goes, all I can tell you is that rooms in the West wing are much, much closer to the pool area, arcade, laundry and the 24 hour quick service dining at Picabu's. Also, requesting a room on a high floor in the center pyramid section of the resort will reduce the likelihood of the dreaded loading dock/dumpster view.
Lastly, I've found their customer service to be wonderful. If you'll be celebrating a special occasion, be sure to email them ahead of time to let them know. Many of us who have stayed at the S/D have received special treats in our rooms. (Again, nothing is guaranteed, but it doesn't hurt to mention it.)
PS - Be sure to visit the
Swan/Dolphin Resort thread, for lots more information and first-hand reports.