I wouldn't register those. Keep in mind that .info names are only $.99 for the first year and you cannot renew them or transfer them any place for that price. It is how they lure you in, then you get shocked when your reg fees are 7 times as high in a year. That is not to say that there are no .info names that are worth it.
Try using one of the keyword tools to help you. Keyword Discovery is my favorite.
http://www.keyworddiscovery.com/search.html . Enter your keyword and the higher the result the better. Google and Wordtracker have good tools as well.
