Yesterday, as I was searching the KB in PartnerSource for some solution, accidentally I bumped on this link in KB,
that the latest rollup for Dynamics AX 2009 SP1 is released, The release date was on 4th July, 2010, but MS has not published this in the PartnerSource > Solutions > Dynamics AX Page. That's strange though!
Anyways, one can view the fixes available and request for download of these fixes from the link below (Please note that it requires PartnerSource Login)
The rollup 5 has one of the fix which we desperately needed to fix one of the issues which we are constantly facing on our DEV AOS box and which I had posted in one of my previous blog http://daxdilip.blogspot.com/2010/06/microsoft-dynamics-ax-application.html