I just so happened to find an ad this morning in Dominican Gateway for a bicycle shop in the area. Haven't been there myself nor do I know anyone who has. It's called Mi Bici at Cana and it's located at Centro Comercial Las Canas (oops, probably the same one jrjth was referring to). Tel 809-469-7550/669-3117. According to the ad, they sell and rent bikes as well as sell parts, accesories and clothing.