My first step before starting the modeling process was to gather lots of reference for the character face (Russell Crowe). As Russel Crowe is a popular actor i was able to grab some reference from 'google' as a starting point. Later I've captured more images from dvd movies to help me define his face better. It was very important to find high contrast images of the actor where his face is lit from a directional light source, this way i can see all the subtle details on the face. Numerous different angles helped alot to "see" the volume of the face. Here are some examples of the initial references that I've used :
Finding good reference for the face makes the project a much easier task because you'll be able to see much more of the face features.
Anyway with or without good references I'm following same steps :)
Here is a short list of websites and search engines where usually I'm looking for pictures:
www.google.com - of course .. the best search engine
www.corbis.com - you can search for your favorite celebrity or random pictures
www.3d.sk - human photo references for 3d artists
www.skins.be - celebrity babes wallpapers or simple pictures. Very good site but with lots of ads with mature content .. so be carefully :)
www.altavista.com - one of the first search engine that I've used long time ago.