BDO Dunwoody LLP: A major Canadian accounting and consulting firm. The site contains useful tax information, such as timely reports on the federal and provincial budgets.
Brendan Moore: Offers Canadian sales tax management and recovery services to complex Canadian businesses and to foreign companies doing business in Canada. Outlines services and profiles key staff.
Canadian Sales Tax Refund Service: Helps businesses and travelers to Canada retrieve some of the sales taxes paid during their visit. Small fee.
Canadian Tax Help: Moncton, NB based personal tax service. Also offer a weekly tax column.
David M. Sherman: An expert in Canadian GST, PST and Income Tax law. Besides his numerous publications, he is also available for professional consulting.
KNV Chartered Accountants: Canadian tax resources , with emphasis on British Columbia.