To change the default search engine in the location bar:

1. Type "about:config" in the location bar and press enter/go.
2. Search for the "keyword.URL" preference.
3. Tap on the preference to change the value. (For example, change google.com to google.com.au.)

Ok I have found the solution. Australian Search Engine Plugins / Search Providers Don't you hate the way Americans treats the rest of world as an add on!

Similar to mbrubecks reply but that didn't work for me and this did:

1 Type "about:config" in the location bar and press enter/go.

2 Search for the "keyword.URL" preference.

3 Right click and select modify and enter the value:

COPY: http://www.google.com.au/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q= to

Copy the above link from http to and including = to Because there is a space in the link and this site automatically hyperlinks things it displays weirdly but copy the whole thing with the space.

Just entering www.google.com.au does not work and the value was blank to begin with so you can't just change .com to .com.au

Mbrubeck's & shmaun's posts are for the location bar only . I tried shmaun's fix and it didn't work for me at first, it just went to some dictionary site and searched for "to". I fixed it by going back to the "keyword.URL" preference, I modified the URL by deleting the space and "to" at the end and now it works just fine. To change the search bar to Google AU simonnrose has the answer. Go to the Mycroft Project site http://mycroft.mozdev.org/google-search-plugins.html . I installed "Google Australia - Pages from Australia" by Mycroft and it worked well right from the start.