According to this article, iPlayer is now all-systems-go for a launch later this year.
On Windows only. And it wont have some things that are on 'listen again', because of a stupid non-reason.
And it's being given out to cable TV people after the Windows release, who already have time-shifting / PVR (Virgin's 'V+' service) functions that are far better than the system the BBC is foisting (for instance, iPlayer can only hold on to a program for a week, and only a tiny amount of series content will be on it. V+ allows unlimited keeping of any content, series or not, and works on any channel too).
And then they'll do a Mac version, followed by Freeview (just in time for everyone to have got one type of Freeview box for the digital switchover, they'll need to get an upgraded box for BBC iPlayer support).
Apparently the hold up is 'third parties outside of the BBC's control', which I take to mean the DRM and peer-to-peer aspects, both of which are proprietary and Windows only at the mo.
Still, at least there are regular reviews, so we can make sure the content we pay for is accessible to us correctly.