Was curious to know, if you register a mispelling of a TMed name, could that be considered a TM infringement?
It depends upon the company. Yahoo had taken down few typo domains by suing them, however most companies do not bother to run after 100's of typo domain owners
http://www.boston.com/business/technology/articles/2006/08/23/microsoft_sues_to_stop_cybersquatters/ Google acquired 2 or 3 supposedly typo domain names via UDRP.
Phonic Similarities is what they go by as far as TM law. Just depends on the overall brand.. my guess a Nike or a Google will chase ya down. Then again look at myspace .. they were stopped by a simple footer text..lol