Pertex, there were programs of varying complexity listed in the various books and magazines, but they tended to lean towards simpler games because people often wouldn't type in really, really long programs.
Compute! for example put out the code for a machine language interpreter called MLX. They would then list the assembly code for more advanced games and programs to be entered using MLX, like a full word processor.
It's great that you guys found a couple of these old books. I wonder how many more are floating around? It would be cool to find them and host them all in one central place.Edit:
Not only have I found a downloadable copy of Island of Secrets, but a whole FTP archive full of these books, plus a couple of collections on scribd as well...
Island of Secrets (and more): ftp://ftp.worldofspectrum.org/pub/sinclair/books/
K-Power Magazine Collection: http://www.scribd.com/collections/29884 ... r-Magazine
Huge collection of Commodore programming books: http://www.scribd.com/collections/30218 ... oks?page=1
That should provide enough entertainment for anyone interested for a little while.