Today, there are a lot of "legal" fake books on the market. It is not unusual for a fake book to have 1,000 or more songs. I have posted the indexes of quite a few of the available fake books in an Excel file you can download from the Yamaya-psr-styles group:
http://groups.yahoo.com/group/yamaha-psr-styles/files/JoeW/

If this link doesn't work, go to the group, select the Files area from the navigator on the left and look in the folder JoeW.

I obtained my first "fake book" about 1960. Tom had it just right. My music teacher managed to get me one for $25. Xerox pages in a notebook, no copyright. I loved it and spent hours each night with my accordion and my fake book. Of course, today there are lots of legitimate fake books. Go to Amazon, Barnes&Noble, or Hal Leonard sites and just search on "Fake Book" -- you'll find lots of choices.

Uncle Dave also hit it right on the head, the performer has to have an intimate knowledge of chords and chord structures to play effectively from a fake book. Since, I think, one has to also have an intimate knowledge of chords to play arranger keyboards, the two make an excellent match.