If the tables have EXACTLY the same layout then why do you have two tables? There is a normalization principle that says that if two different things have identical structures, they really aren't two different things but rather are improper subdivisions of one thing.
You could merge the tables by adding a field that says "this record came from table A" or "from table B" (if that was really needed.) There is often something wrong with a design that requires this kind of data shuffling.
What are you trying to do? (Answer that in English descriptive terms, not in code.)
EDIT: Obviously, theDBguy is faster than I am at typing.