Hello, i am a newbe in Haiku, but i am very interested in this Project.
I am very interested in Programming. As i saw on this page, HAIKU is an Open Source Operating system, so where can i get the whole source code ? I have already searched in the HDD Image, but i couldnt find it. I would be vvery happy about a fast reply 
Itâs easier to find than you think! 
At the top-right of this page, youâll see the âDevelopmentâ link and it goes here:
http://haiku-os.org/development
Where youâll find all the information you need to get the source code and start building it.
Because Haiku is not an official release yet, the source is not yet distributed with the image (it would make the image at probably 4 times as big!) and there are currently no ânightly tarballsâ or anything like that. You will need to obtain the source directly from the SVN repo hosted on berlios.de (see instructions on the development page).
One more thing - if youâre on Linux, FreeBSD, or even OS X, you will need to consult this page as well:
http://haiku-os.org/documents/dev/getting_linux_developer_tools
if you wish to build Haiku from one of those environments.
WOW , That was fast So i dont really understand the things written on the page, maybe because i am a newbe in HAIKU. I am now currently working in HAIKU, i opened the Terminal and typed : svn checkout svn://svn.berlios.de/haiku/haiku/trunk haiku (Than i got : sh: svn: command not found. What do i make wrong ;-)?
Haiku is not capable of building itself yet - itâs certainly not stable enough yet.
You will need to obtain and browse the code from another OS - Linux, or BeOS R5/Zeta would be my suggestions.