A lot of product managers have a love/hate relationship with roadmaps. Many times with good reason, as misinterpretation of a roadmap can sometimes cause more problems than the roadmap serves to solve. It remains true however that roadmaps, if used right, can be a very useful tool to communicate progress in product development.
There are many techniques available to create and present roadmaps. However, there are certain best practices that can be applied regardless of the actual technique or tool that is used.