Support will be as per support policy however the binary and license key for the above will no longer be available after the 15th August.
For users who are still requires the above, do remember to download and keep a copy.
Please refer to the announcement here.
For Support matrix refer here. Click on Lifecycle Support Matrix.
Update 21st Feb 2013
Even after 15 Aug, you are still able to purchase vSphere and downgrade via the myVMware portal to vSphere 4 and use it to license the ESX 4.x. EOA does not restrict user from downgrading. Downgrading to vSphere 4 will be disabled only when the product has End of Life (EOL).