Praise be to Allah.
There is nothing wrong with making use of free books that are available on the Internet, by reading them, saving them or printing what you need of them, because they have only been put on the Internet for that purpose. See question no. 38847 .
Similarly, there is nothing wrong with downloading free computer programs and apps that are available on the Internet.
The basic principle is that it is permissible to download those books and programs, and the responsibility is borne by the website that published them, if the authors did not give permission for that. The one who browses websites is not obliged to make sure that the author of every book or program has given permission for downloading it.
And Allah knows best.