Just seen this on GMTV,also in newspapers,but does'nt seem to say which sites etc, I take it must be all third party sites.
Ryanair Cancels Thousands of Tickets
From Monday 11 August 2008 Ryanair will cancel thousands of tickets bought through "price comparison" sites, because they don't want anyone to book without visiting the Ryanair site. They say that they will refund the fare (which remains to be seen) but if you have a holiday hotel booked, how much does Ryanair plan to charge for an alternative flight when you turn up at the airport to find that your ticket has been cancelled? See our Press Stories page