Here are some useful publishing resources for authors and publishers:

Publishing Resources for Canada:

To acquire and ISBN (I believe ISBNs are still free in Canada):
Collectionscanada.gc.ca/isn/

Invaluable information for Canadian publishers:
Publishers.ca

Canadian lntellectual Properties Office

Information on Legal Deposit:
Collectionscanada.gc.ca

Publishing Resources for the US:

Here you can acquire library cataloguing information for the US and apply for CIP, LCCN, and PCCN:
The Library of Congress

ISBNs for the United States can be acquired here. This is where you can also find SAN and Barcode information:
US ISBN Agency  or BOWKERS

You can acquire official copyright certificates and information here:
US Copyright Office

Useful information on the International Standard Book Numbering (ISBN) system:
International ISBN Agency

Publishing Resources for the UK:

Here you can acquire an ISBN for your book:

Nielson UK ISBN Agency

Here you can acquire official copyright for your book:

Intellectual Property Office

Here you will find information on legal deposit for print books in the UK:

British Legal Deposit

Here you can acquire information on the UK's Cataloguing-in-Publication Programme:

The British National Bibliography

These are two great Print On Demand websites:

Createspace.com

Lulu.com

Kindle Publishing

EPUB Publishing

Lulu.com

Smashwords.com

Kindle for PC