Upvote:4
http://www.edreams.com/offers/flights/airline/ has some user reviews of airlines, but also check-in and baggage information for the major companies.
Another site with such information is SeatGuru: http://www.seatguru.com/browseairlines/browseairlines.php
http://www.airline-baggage-fees.com has useful information, but only for baggages.
The most reliable resource for this information remains the official site of each airline. Here is a list of links to the pages of baggage information for many of them: https://www.kayak.com/airline-fees