wwwmyspace.com, a common misspelling of www.myspace.com, receives an estimated monthly traffic of 150-200K visits (source: compete).
IT security company McAfee has an interesting report out that describes the economics of typosquatting:
"McAfee’s research shows that almost a quarter of all suspected typo-squatted pages use Google or Yahoo! advertising. Our research confirms the anecdotal evidence that the ease of using Google’s ad syndication program helps makes typo-squatting profitable.
In a twist of the tables, though, Google has fought typo-squatters of its own domain. We’re not surprised. Our research ranks Google.com as the 15th most typo-squatted domain we studied with 32.2% of its 289 permutations hosted by live parking pages. Ironically, we detected Google syndication text on 43 of those pages."
-- via Domain Tools
Also, a feature story from last May in Business 2.0 about some of the most successful domain name speculators.