>Tell all your existing, un-paying customers that in 30 days, you're going to start charging $19.99/month for it, but if they sign up before the pricing starts,

>Tell all your existing, un-paying customers that in 30 days, you're going to start charging $19.99/month for it, but if they sign up before the pricing starts, they're in for $9.99 (or $12.99--whatever floats your boat). Leave all your existing customers happy by not charging them more. This sounds a bit like pulling the rug out from under his current users. Perhaps a better idea, if the OP has the time, would be to implement new features in order to try and convert some of the free users. And every time a new feature comes out, announce it to all the users, reminding them how much better the paid experience is. That's how freemium works isn't it?