I was going to apply a few months ago, but decided on easyJet instead...the salary isn't anywhere as good as Ryanair, but at least all the training is free.
I do have to add though that Ryanair are by no means the only airline that charge for training. A similar system exists in many other airlines, Varig of Brazil also expect you to fund your own training before even applying for a position with them.
As someone else mentioned, there will be plenty of people willing to invest the money, so as long as that situation exists, Ryanair will keep on charging.
rgds