Is it okay for me to make a reference to "Batman" on my retail sales website (and in my brochure) without violating any trademark or othe laws?

If you are selling real BATMAN products, you can use the name to describe what you are selling.  It would be unfair competition for you to capitalize on the BATMAN trademark to make money.  You cannot simply use it to capitalize on another's investment of time, energy and resources to develop the brand.  However, if you are using the mark to describe an attribute of a product you are selling, you may be entitled to use it under the fair use doctrine.  The fair use doctrine forbids a trademark owner from maintaining a descriptive term for exclusive use and preventing others from describing a characteristic of their goods.  You can use it where there is no descriptive substitute to describe what you are selling. 

DC Comics has 18 Federal registrations of the trademark BATMAN for use on a wide variety of goods and services. You can check them at www.uspto.gov, by searching in the Trademark section. A third party, Gotham City Networking, applied to register the trademark GOTHAM BATMEN and DC Comics has opposed both applications. Whether you are infringing and whether your use would be unfair competition can't be said without a legal analysis of all of the facts, but it appears that DC Comics polices third party uses of BATMAN and would likely object to your use.