Profiles of climbs
The finest online profiles of climbs in Europe are found at the Altimetrías de Puertos de Montaña site. The site is available in different languages, but try using the spanish one so not to miss out on information. It focus on climbs in the Basque and surrounding provinces of Spain.
The biggest archive of profiles of climbs on the Internet are found at Swiss site Salite.ch . There are over 9000 profiles right now. The profiles cannot always be totally trusted, but should give a hint of the actual profile of the climb. (Try searching on starting places as they may have odd/unusual names for the climb goal, if you do not find what you are looking for.) I find the sister site at Zanibike is easier to use when researching a special area within a country (ex: Italy, Lomabardia, Sondrio area could more easily be presented).
CicloManiac has quite a lot of profiles of climbs too and usually with a little more information than Salite.ch.
The best offline source for profiles are found in the very good books published by Altigraph in France.