There are many sites that have information about Roatan. Rather than reinvent the wheel I am happy to direct you to them.
General description and history of Roatan on Wikipedia.
Various sites on vacation and travel
Even though I am a Realtor on the island. I am not worried if you take a look at other sites by my fellow Realtors. Just come back after wards :)
Steve Hasz has some good information and it also has links to vacation rentals.
Bob of REMAX has some good property info on their website