A: Most broker sites (e.g. CommSec, Nabtrade) publish information around companies going ex-dividend. Also:

1. Most companies publish a financial calendar – which includes details of expected dividend payment dates and ex-dividend dates. Visit the company’s website;
2. When profit announcements are made, details of dividends and ex-dates are also announced;
3. Typically, there is not much variation from one year to the next. So if (a) or (b) doesn’t help, have a look at what happened last year.