According to this article on corporate mentoring programs,"About 70% of Fortune 500 companies offer mentoring programs." And the article discusses how some companies--and employees--handle the process of finding a mentor. For some companies, it's more automated than it is for others.
At Management Mentors, we don't recommend automatic matching software. We recommend precision matching, which allows for the human component and can help diminish the number of matches that don't work (we have 90 percent success rate in matching). Still this is an interesting article and worth the read.