Some of you may know this already, so feel free to skip to the list if you already know. Most of ZodTTD's software are what are called ports. Changing existing programs so they work on a different platform (iPhone) than the one they were written for. (PC, GP2X or PSP for most of Zod's software). To do that, you need the program's source code. Which is where open source software comes in. Some developers charge for their software. Others decide to release it for free. Others again release it as open source, which means that both the program, and the program's source code are available. A lot of the programs are licensed under what is called the GPL. The GPL is very complicated, but the short of it is that if you base an program on another GPLed program, it is a derivative work, and you need to release the source code (which allows someone else to make the program for themselves, and possibly release it). You are still allowed charge for it, but you have to give anyone who pays for it the chance to obtain the source. Yes, this does mean people can then legally recompile the source code and distribute it for free. (Not the same as pirating, where you just download the binary without paying and redistribute that). An example of where this happens is with the IRC client XChat. Some of the programs are licensed under BSD, MIT or a few other similar licenses, which basically mean "Do whatever you want." - No problems for Zod there. Some are licensed under non-commercial licenses, which means you are not allowed to charge for it. ZodTTD used to provide the source code for his programs - in fact you can get out of date source code from his github account: http://github.com/zodttd . However, the GPL requires up to date source code. If you want to be kind to Zod, you can call it neglect, if you want to be suspicious, you can say it's because he is now charging for the software. So here is the list of all license violations by ZodTTD: psx4all v2.0.1 (and every other version since 0.6.0): PCSX (PCSX is GPL, no source provided for Zod's derivative app) - http://pcsx.net CDR plugin (GPL, no source provided) - http://mooby.psxfanatics.com (site defunct) Pete's SPU plugin (GPL, no source) - http://www.pbernert.com/html/spu.htm n64iphone v0.8.1 (and every version after 21 Dec 2009): Mupen64Plus (GPL, no source provided) - http://code.google.com/p/mupen64plus/ Mupen64 (GPL, no source) - http://mupen64.emulation64.com/ Glide64 - http://glide64.emuxhaven.net/ or Rice Video - http://en.wikipedia.org/wiki/Rice_Video (It's using one of these, both are GPL) snes4iphone (all versions on RockApp or Cydia Store): snes9x (no commercial derivatives allowed). - http://www.snes9x.com/ (snes4iphone is based on Dr. PocketSNES which is based on PocketSNES and SquidgeSNES which are based on snes9x) gameboy4iphone (all versions released after April 28, 2008 - http://github.com/zodttd/gameboy4iphone): gnuboy (GPL, no source, no site found) Historical Some developers have previously taken action against Zod for misuse of their source code. OpenTTD (GPL code, incomplete source. Proprietary graphics ) -See Rubidium's comment: http://www.zodttd.com/wp/2010/04/open-up-openttd-to-apple-devices/) Mame4iphone (No commerical derivatives)- http://www.emuchrist.org/emulmao/2k9/08/ZodTTD_MAME/ gPSP (GPL, but Zod got the original author to allow him to use it without the GPL) The openTTD issue was straightened out, and eventually approved by the openTTD devs (but not by Apple for the App Store version). He has started distributing mame4iphone stressing that he takes no donations for it, though I don't know if the MAME team are aware of it. Considering that he is a community source, and that he has many featured apps on the Cydia Store, and some of the most popular jailbreak apps, he should really clean up his act.