Is this an effective obfuscation technique? Long ago I created a simple program which obfuscated a file by taking the first byte, then XORing it with the second, taking the (original) 2nd byte and X-ORing with the 3rd, etc, down the line. The file size is unchanged, and I could invoke the same program to undo the obfuscation. No key or password was required. It was just a simple way to hide the contents of a file from casual view.

My Question Is: Does this result in a uniform distribution of byte values such that it appears to be encrypted, and the usual analysis would not turn up anything?

I know that this is not encryption. Also that the first byte is plaintext, but one could simply stick a random value in the source file, use a space or some other harmless byte there.
It sound like you're using something like an XOR cipher to obfuscate your code.  It will appear to be encrypted, but this can still be broken by frequency analysis since the use of a constant shift means that the encryption effectively has no key.  An example of how to break a similar XOR cipher can be found here.  As @iismathwizard mentioned, decryption requires no more knowledge than the fact that XOR is in use, in the same way as as ROT13 cipher might be broken