has figured out a way to overlay the complete set of nautical charts for United States, New Zealand Brazil and the United Kingdom over Google Maps which allow you to pan and zoom with ease. They also have a feature where you can drop waypoints and create custom routes which are saved to your free account.
What is really cool about the site is that you can export out those saved routes and move them over directly to your Garmin GPS unit via the Garmin Communicator Plugin
GeoGarage is free but you need to pay a subscription if you want to access the UK charts. The reason is because GeoGarage is required to royalty fee to display them online.
No word on the future of Canadian charts on GeoGarage but if they were rolled out it would likely be part of a paid subscription since Canadian charts are not available for free like they are in the US.
By the way, are you interested in downloading your own NOAA charts for free? Grab them directly from the NOAA here
More info: marine.geogarage.com