World Wide Web: Language Usage Apps

If you edit on the go, you may be interested in an app version of Garner's Modern English Usage (note it is American usage). A recent article on the An American Editor blog reviews the app, and is particularly impressed with its discussion of 'the battlelines' in usage (this discussion is also in the print version, of course).

For British English, you can also get the Oxford A–Z of English Usage and Practical English Usage in app form.

What is out there for Australian English? Not sure about language usage, but the Macquarie Dictionary has a number of apps.