Without knowing what is contained in my parents will, my older brother is the executor of the estate and has not told me or the siblings who gets what. My older sister wants certain pieces of furniture without consulting me or my two brothers. Is there any legal means which can be used to prevent my sister from taking furniture and other valuables?

Has the will been probated? You can check with your local probate court to see. If it hasn't you should be able to force it to be probated. At that point your brother will be responsible for cataloging the estate and to maintain an accounting of how its distributed.

Also you referred to your "parent's" will. Generally wills are individual, because its unlikley that both parents will die at the same time.