I found the page today when there were seven clues already. It was a fairly easy task to crack the code, just time consuming. It helps a bit if you have heard of the Huffman minimum redundancy code, which is a quite interesting algorithm. I figured that I could create a script to solve the code at least to get the decimal numbers and their frequencies but came to the conclusion that writing the program would take more time than creating a quick macro to cut the l--ll-ll---llll- series into groups of three and then search'n'replacing them with their decimal equivalents. Hey, eight search-and-replaces isn't a big job.

By the way, there's an error in one of the clues... Luckily it's not very fatal.

You might also get some kicks out of this pdf, letter frequency counts in English or the following html-document: http://deafandblind.com/word_frequency.htm