I've recently been able to register typos that have immediately gotten 30+ uniques a day, recently as in within the last 2 months. You have to know where to look, and beat people to the punch obviously.
I will say though that to get any REALLY good typos anymore, you have to be really early on them. I have an adult typo getting over 100 uniques a day, but at the time I first knew of the main site enough to get the typo, it had just been launched maybe a month or 3 weeks or so before, and had really jumped up in Alexa but still in maybe the 5,000 - 10,000 Alexa rank range and my typo was getting about 20 uniques a day. Now the site is in the 800s and still going up. So it was snapping the opportunity AND more or less getting lucky on the site doing well. Still though, you can't expect to spend 5 minutes a day looking up typos and finding really good ones. It takes research.
WordTracker, but honestly in getting typos now, the only place I use anymore is Alexa. And I'm sure 90% of people trying to get typos using Alexa would fail because there's a certain science to it. I have one typo of a non TM'd 5-letter .com site that I got not too long ago (couple months maybe) that is paying me about $2 a day that I got using Alexa. And the typo I got has no Alexa rank.
