I'm putting together a license for some code I wrote. I was planning on doing a dual license, commercial open source, something like SugarCRM. they use a modified version of the Mozilla Public License, but reading over it, I saw something about allowing others to charge a fee for their modifications of the code. I was wanting to aim more for GPL I think. I'm not completely sure, but I think code under the GPL license can not be modified and sold by other people, can it?

my intent is to make my code open source. allow people to use it all they want for free, or modify it, but not be able to resell the code in any form, keeping the majority of the modifications in the origional code by the main programming team.

My understanding of the GPL is that you can absolutely modify the code and sell it, just that you also have to allow users to have the source code including the modifications. I think that you controlling the original code is more of a copyright issue where if they modify the code and you disagree with their modifications, they can't call it ProgramX anymore. They would have to fork and call it ProgramY... (note that I'm not a lawyer, maybe email the FSF)... http://www.gnu.org/licenses/gpl-faq....lowDownloadFee

would it be legal and acceptable for me to add a section to the license stating forks of the code may not be charge for and only free open source?

I'm no lawyer, but I doubt it. Read through the FAQS section I posted above. It seems like you could publish your code under GPL and I could still sell it if I wanted to, as long as I supplied the source code with it. The deal is, say Joe bought the program from me and asked for the source, I would have to give it to him. Then he could post it for free since it's GPL and also redistribute the binary for free...

that's a little better.. at least I could post free copies of the forked code on my own site. what about a section added to the license stating the origional developer must be granted a copy of the forked code free of charges? have any developers ever added modifications to the GPL?

Don't know, I'm not a developer either, just a linux junky. But there's been this battle between Sveasoft over their use of GPL firmware on Linksys routers. They basically got torqued because someone who purchased their firmware released it to the public, which seems within the guy's rights since it's GPL...

http://www.gnu.org/licenses/gpl-faq.html#ModifyGPL

it looks like is it doable, just not likable. and with any self-written license, just as much time should be put into the license as is put into the product it covers. licenses and modifications to them shouldn't ever be taken lightly. it could mean the end of your product all together.