DIAC is introducing this model from July 2012.
The Model is proposed to commence on 1 July 2012. As of this date, new applicants for independent, family or state/territory sponsored migration would need to submit an EOI and be issued with an invitation before lodging a visa application, unless eligible for transitional arrangements. The first round of invitations is expected to occur in January 2013.
Transitional arrangements currently apply to certain people who, on 8 February 2010, held or had applied for a Skilled – Graduate (subclass 485) visa. This group is able to apply for a permanent skilled visa under the previous system, until the end of 2012. There are no additional transitional arrangements in relation to the Model.
More info on: http://www.immi.gov.au/skilled/general-skilled-migration/skilled-migrant-selection-model.htm
FAQs: http://www.immi.gov.au/skilled/general-skilled-migration/pdf/model-faq.pdf