I perused the website and it looked pretty comprehensive to me, if nothing else, anyone who seriously studied this page and learnt by heart the proposed "56 rules" and guidelines would surely master the small lacunae the author admits his site contains.
However, in my opinion, the interminable single page layout is outdated and user unfriendly; difficult to scan, intimidating for English learners, and ironically, too detailed to offer any immediate help.
Furthermore, Mark Rosenfelder's suggested computer programme, Sound Change Applier, sounded horribly complicated to me. The one thing it appeared to be missing, one of the most useful aids for English learners wishing to improve their pronunciation, was an audio reproduction of the IPA phonemic chart (perhaps less important for native speakers who wish to understand the orthographic rules governing English spelling). Instead, the author has created his own phonemic chart.
If we're discussing spelling, we have to discuss sounds as well; and
this means choosing a reference dialect. I'll use my own, of course--
a version of General American that's unexcitingly close to the
standard. I'll call it GA below.
In using his computer programme one would benefit in hearing the pronunciation but as I previously pointed out, it doesn't look easy to install and I suspect it would not work on today's various operating systems; Vista, Windows 7 and 8, or even Mac.
I wonder how useful would the following be to future visitors, if we suggested that they visit this site and they came across this explanation:
(number) 6. aught and ought become òt: daughter = dòt@r, sought = sòt.
8. Elsewhere, gh is simply dropped: freight = frät.
14. ci or ti becomes $ before a vowel: gracious = grä$@s, nation = ä$@n.
As much as the idea and concept of this web page appeals to me, I would not recommend new users to visit this website. In the past, I have often advised Italians wishing to improve their English to listen to pod casts, visit the BBC learning English page which has a section dedicated to pronunciation; EL sites which do dictation exercises; e.g. http://www.dictationsonline.com/, and to watch videos and DVDs with English subtitles.
Another excellent source are online dictionaries. The majority of whom supply audio recordings and give the phonetic transcriptions of individual words.
In conclusion, I agree that we need to recommend resources to users asking for guidance, it's not good enough to fob visitors off by saying, “English pronunciation is quirky, deal with it” but Mark Rosenfelder's Hou tu pranownse Inglish isn't the answer.
I happened upon this clear and unambiguous guide, from OALD, explaining the phonemic symbols used in the dictionary, they include both British and American pronunciations. I imagine that the purchased online edition would also contain the audio recordings of each and every word too.