Changes to General Skilled Migration in respect of skills assessments will commence on 1 January 2010 where as Applicants for Subclass 885, 886 and 487 visas will have to obtain a skills assessment at the time of application ( rather than just having applied for a skills assessment).
This change does not affect subclass 485 visa applicants
http://www.immi.gov.au/skilled/general-skilled-migration/pdf/skills-assessment.pdf