Is there any open source or free software that can do code obsufcating?

meaning to mess up the code to stop people from tryng to copy the code
anyone has any idea?

First of all, i wouldn't worry that much with obfuscating if I was you. Most people doesn't even know that .NET assemblies can be de-compiled.

Second, you should try and figure out if you have any code in the application that compromises its security. If not, a medium size application will be large enough to give a lot of work for most people in de-compiling the assembly. If you're planning on hiding that special component that you reference in your application, then people will always see it and use it if they want to. If you're just planning to hide that special functionality that took you days to find in the Internet, then if people want to they can as easily find as well.

Third, you will need to find out if you have some sort of state-of-the-art alghorithm that must be protected. In most cases you will not have something like this, so, there is no need in doing it. If you have the ability of developing this sirt of alghorithm, then you will certainly have the knowledge of developing in a lower level language. Obfuscating wouldn't be an issue in this case.

Last fo all, .NET technologies can easily reference COM components, and COM components can easily reference .NET assemblies, so, put the important security code in a Win32 DLL and reference it in the .NET project. If you're not using in any visual fictures in the Win32 DLL, then it should be almost like copy/pasting from C# to C++ (if you use .NET classes, like System.Int32 or System.String), and you would have any sort of problems i the returned types as well.

Just remembered another thing.
When you de-compile a .NET assembly, you will only see the external entry points in the original development names. Any variable that you declare inside a method, that has that method as its scope, woun't be in its original name. Also, all private methods are renamed as well in IL.

Another thing, is to develop in your home country's language and not english. If you're developing in a language that is not english/french or any of the latin ones (Portuguese/Spanish/Italian), then obfuscating is already done. Most certainly, people will not know more from a method just be reading its name.

i am developing a php web project

There are several applications you can use to obfuscate your php projects. Search in google by Zend Guard or Php Lock it.

If you´re planning on installing your project in a windows machine, you should look for any installer software that might do the trick in exporting your application. Keep in mind that you will need to configure your web server for your application, so, you either export the web server's configuration files as well, or you have to do it afterwards "by hand".

Yf you're planning on installing the project remotely, then i should advise you in doing it folder by folder (FTP). Don't forget that in the end, you will need to configure the reading/writting/executing permissions in the files you export.