So if you're looking for a catalog style pedigree for Fluffy by Big Stud, out of Princess Fluffy by Other Big Stud, you would Google:
"Princess Fluffy" "1st dam"
If you don't find anything, try the 2nd dam's name & then the 3rd dam's name. Most Keeneland, Fasig-Tipton, OBS & Barrett's sales catalogs come up, along with some of the European & Australian catalogs. Check the year of the catalog & hope for a 2010 or a 2009, for most recent information & if you are lucky, you will find a 2010 catalog where "Princess Fluffy" really IS the 1st dam (because that Google search will also bring up any catalog-style pedigree with "Princess Fluffy" in it, whether she herself is the 1st dam or just a horse mentioned somewhere under the 4th dam). Anyhow, Google tends to return most recent, most relevant first, so in the first couple hits, you get more information on Fluffy than you will when "Princess Fluffy" herself is under the 4th dam (and most of the good information relates to Fluffy's 3rd cousins once removed).
Good luck. It usually works if a member of the fairly immediate family has gone through public auction in the past 5 years or so.
And it's free!
Hidden Echo Farm, Carlisle, PA -- home of JC palomino sire Canadian Kid (1990 - 2013) & AQHA sire Lark's Favorite, son of Rugged Lark.