It is not a one time code
There is no mathematical formula
There is no random numbers used
It doesn't use any of the normal encryption packages / methods AFAIK
Probably easily broken.
It is not a number base algorithm
It is not a bit shifting or binary operations algorithm
It is really simple
Almost anyone can do it, once they know how!!
Substitution ciphers are one of the most common ones used. It would actually be one of the first I would test by running a frequency test (Like this tool http://vorpal.nebrwesleyan.edu/~mcclung/ciphers.php) and then just fiddle with it for awhile (It becomes apparent after a short while if a substitution cipher wasn't used). The chances are the most common letter would be a E and then T, A and so on. So start replacing them and start seeing if you can get some clear words going. You can also look for common letter combinations in the text also for common words.
I was working on it also and found out it was a subsitution right before firedraco posted it :(.