Software protection at the source code level allows the use of several methods that are not possible with compiled binaries.
Here you can download the demo version of Obfuscator. Installation & application files are all digitally signed and tested with the latest antivirus software.
Here is a sample "Hello World!" application in three forms: source code, clean compiled, and obfuscated.
Feel free to analyze the difference between the original file and the obfuscated copy. If you don't know how, you might want to read my articles about reverse engineering.
If you would like to ask me about Obfuscator, or something's not clear, mail me. I'll be happy to answer all of your questions.