Question of the day: can one look for a mentor in the writing business and how?
Absolutely. I assume that you mean formal mentor, which I'll get to in a second, but I also heartily recommend befriending writers whose careers you admire because often times, if they're generous (and many writers are), you can learn simply by example. The best place that I've found to do this is on FreelanceSuccess.com, where people dole out info and advice by the bucketfuls on the forum, and are always willing to advise you on whatever your dilemma/question, as long as it's not too, too insipid (and this is a high bar, so don't worry) and as long as they have an actual answer. (Thus, if you post something and don't get any replies, it's likely that no one knows the answer, not that you smell.)
As far as formal mentoring, I do know some writers who offer guidance and classes and such. I don't want to name them personally because I'm not sure if they're looking to take on new clients, but I welcome people to post names and referrals below. Alternatively, consider contacting associations such as ASJA or even Mediabistro. I know that ASJA has a formal mentoring program that it offers at its conference, and you might be able to hook up with someone throughout the year as well. Other than that, consider sending a writer whom you admire a note and asking him/her to BE your mentor. Several people have written me in the past to request a mentorship, but I've never been comfortable taking money from fellow-writers (and frankly, I never really had the time to take this on), but definitely, some writers love mentoring, and they'll jump at your request.
I'm sure that there are other great ways to find mentors: readers want to chime in with ideas?