I want to know which is the best method to encrypt php scripts for distribution ?
I would recommend IonCube, we have used it for years and have had no problems with their solution.
We actually also have Zend Guard, but the majority of our clients want IonCube encrypt files.
Another good thing with IonCube is that they have a online solution where you can encrypt just the files you need and just pay for those files, instead of purchasing the software. So that might be an option for you if you dont want to spend that much money on the software at the moment.
Zend but unfortunately that costs a lot of money.
There are others out there but unfortunately they’re not supported by default like zend seems to be.
I’d suggest you find someone who has zend and offer to pay them for the encryption of your code. Also in case your users want to mod the system somewhere (EG use plugins) i’d suggest you only encrypt the core of your system so that it can’t be used without your core code but can still be used with external code. This encrypted code could of course have code which makes a check to your licensing server to check its licence is valid 
How about the loaders it might make a problem as server require a loaders ?
Zend and IonCube both required a loader, how about the products addons as that’s what I am working on and it seems it have to be loader in server to put in directory to make it work, or the server have the loaders
I think both zend and ioncube are installed by default on most linux servers.
As mentioned in my previous post others are not.
I’ve been using IonCube’s online encoder, since it’s a less expensive method for infrequent use. Yes, most respectable hosts provide Zend and IonCube loaders on their servers.
@RedDevil and Force: Thats a very handy tip you’ve just provided.
Looking at the standalone encoder $199 is pretty good. I might buy that…