Does this mean no more secuirty updates for Leopard?

I'm not sure but I know security updates were still showing up for Leopard when all the rest of the machines in the house were running Snow Leopard. I would imagine some security updates will be "high priority" and get pushed all the way back to Leopard but it wouldn't surprise me if regular Leopard updates stopped coming now that it's 2 versions old.

I'm curious as well because my wife's old G4 Mini is sitting at 10.5.8. If updates were to stop, I'd be inclined to consider replacing it with an Intel Mac.

 

Pretty sure Leopard got left out of the Mac Defender patches. Although I don't know if that means MD did not affect Leopard, or if Apple is just not supporting it for all security issues.

 

Apple has never had a public support policy, but that's the way it's always worked.

Current version (call it 10.x) gets point upgrades (eg. 10.x.1, 10.x.2...) which may add features or fix non-security bugs, as well as security updates. That's Lion now.
Previous version (10.x-1) gets security updates only, no other fixes. That's Snow Leopard now.
Older versions (10.x-2 and older) get nothing. That's Leopard now.