How to make a program free

• Always accompany your software with a LICENSE.TXT file
• On the top of each source file, write
  • Copyright© 2002, 2003 Name Surname
  • This software is released with the terms contained in LICENSE.TXT
• Use one of these three licenses
  • GNU GPL: for programs that should remain free in any case, whether modified or not
  • GNU LGPL: same as above, plus it allows linking with GPL-incompatible programs
  • New BSD or MIT X licenses: no restrictions, for programs that should have maximum diffusion