I did it, like, once in school. We used a funny DOS application to decode a txt file, we used it to calculate all the frequencies, and then compared it to a table with English language letter frequency list. That was years ago, though, and I hardly remember it.
http://www.counton.org/explorer/code...y-analysis.php
http://www.simonsingh.net/The_Black_...equencies.html
The funny thing is these are non-standard characters and will require some busywork to analyze that