Well, I think that we have discussed this again a long time ago... never mind!

I see a lot of people porting games or utilities to MorphOS from other platforms and I asked myself why not me?

But I don't know how to start, what tools I need to port some source to MorphOS to make it executable, what knowledge of a programming language.

I think it's not only me that wants to know how to port games and tools to MorphOS, and more people porting the better for our platform.

I will really appreciate if somebody writes a step-by-step tutorial how to port to MorphOS.

As you don't (seem to) have much earlier experiences in porting, wouldn't you be a perfect choice for writing such a tutorial?

What you need:

MOS SDK (from http://developer.morphosppc.com/)
Tinygl SDK
PowerSDL SDK

Those should help in the beginning...

Also, it might be a good idea to try compiling some simple example programs first.

also a small portion of programming knowledge would be helpful

I must say that I agree with Phantom. I have some programming knowledge (very general, I've wrote several scientific programs, but never on MOS - I've only wrote one app in MOS so far).

I would very much like to help MOS by porting some apps (at least some games and small tools), but I don't know how to start. A tutorial, or even a few "guidelines" would be greatly appreciated.

Get the Amiga Dev-CD.
The ROM Kernel Reference Manuals and Autodocs are on it.
The MOS specific Autodocs are in the MOS-SDK.
Look at some Unix Documentation like www.unix.org and off you go.

Phantom :

The given answers represent excellent advices : To port programs you need a general knowledge in programming and you could start with simple SDL examples.

If you want to port programs from UNIX you also have to understand some UNIX specificities.

Last, I wrote a document that could be useful for you to learn some things about the differences between the several Amiga systems, explaining how to write portable code : http://main.aminet.net/dev/cross/PortableCode.lha

This may help http://amigadev.free.fr/PortableCode-en.pdf

Thanks a lot mates