Hi Romeshg,
Welcome to the Aussie section.
As far as I'm aware (I'm not an agent) there should not be any issue when you arrive in June 2009 since the visa doesn't expire until August 2009. If it's a joint visa with someone else make sure which one has to enter first or at the same time.
Issues may arise if you need to leave the country after August 2009 since then you will have to apply for Residents Return Visa (RRV) to get back into the country if you leave. To get an RRV they like for you to have been in the country for 2 years. So if you leave your entry until 2009 you may not be able to leave Australia until 2011. For more info on RRV see
here.
Regards,
Karen