Without Search Suggestions
Just by visiting the site, Chrome should have already stored it as a search engine. Just go to Chrome's search engine settings and find duckduckgoog.com in that list, then click "Make Default" next to it.
With Search Suggestions
Unfortunately Chrome can't auto-discover more than one search per site, so if you want to use search suggestions, click this link. Note that after doing so you'll probably want to go into Chrome's search engine options to set it as the default search by clicking "Make Default" next to it.
Click the little dropdown arrow in the Firefox search bar, then click "Add DuckDuckGoog" to save it--note that you can choose to use search suggestions or not. You might have to click it again to make it your default.
Visit this page with instructions and use the following URL as the search string (or see below if you want to use a localized Google URL):
DuckDuckGoog should be easy to add to any browser or launcher (Alfred, GnomeDo, etc.) that supports custom searches.
Just use this search string in your browser/launcher's search engine options to create a custom search:
(Replace SEARCH with whatever your browser/launcher expects the placeholder to be).
If you would rather make DuckDuckGoog search google.com.au or google.co.jp etc., than the default encrypted.google.com, then just include that in your search URL, using something like
For example, if you use Chrome and want to default your Google search to Google Japan, use this:
Note that if you use Firefox, you don't have the option to manually change search engine URLs like that, so you'll need to install an addon of something like Mycroft that allows you to do this.
If you have issues, feel free to email me.