Most commonly, "Books in Print" is just a list of all the books currently in print. It's published by R. R. Bowker (the guys who assign ISBNs). This is a reference work for bookstores that allows the clerks to find the ordering information when someone walks in to special-order a book.
When your pals at PA said that information about your book would be sent to every bookstore and library in the country, what they meant was that your book would be listed in Books In Print. That happens automatically and without further charge when you assign an ISBN to a book. Yes, every bookstore would have a copy of Books In Print. No, it isn't the same as sending around a catalog or a salesperson. BIP lists title, author, publisher, ISBN, release date, and price, arranged in various ways for easy lookup.
BIP is on the web these days, but you need a subscription to use it.