Any advice you can give would be greatly appreciated. I will be there 7/28-8/2 with a group of 6 people.

Here are a few links;
http://www.sunnydayskeywest.com/
http://www.keywesttravelguide.com/snorkel.html
http://www.wilddolphinadventures.com/
Do a Google search and find much more info.

Thank you for the links! I had googled already but was a little overwhelmed by the choices. I was hoping someone would post about their positive experience with a company/guide. Thanks Again!

My husband and I were in Key West this past March and tried Danger Charters. We did a half day snorkel where we also went kayaking through the mangroves. I highly recommend this charter and the service was impeccable! - Susan

Here is the link:
www.dangercharters.com

We went with Sebago in March and it was FANTASTIC!! We did the Island 'Ting, which included breakfast on the way out to the reef, snorkelling on the reef, sailing to a quiet shallow place for lunch, all you can eat lunch, kayaking and swimming after lunch, and then cookies and fruit in the afternoon before sailing home for the day. The boats are large catamarans, but not so large that they are overrun with people. There were around 30 of us on the day we went out and there was lots of room for relaxing/sunbathing (sit near the back and you can just hop up on the side/back behind your seat). The crew was fantastic too. Oh - did I mantion that it was all you could drink? Two kinds of beer on tap, homemade sangria and non-alcoholic beverages too! We will defintiley be booking them on our next trip!

I've heard fabulous reports of Danger Charters (apparently no danger whatsoever, and a very eco-friendly trip), and the Island T'ing.

Our own personal experience with Floridays was absolutely delightful. They limit passengers to about twenty and have a great sailing vessel. They dock at the Hyatt on Front Street.

These are perfect suggestions! Thank you all so much!