But at least it is better than transliteration. For web purposes, I'm now using SPIonic also. It's very easy to use. It's very similar to the TLG Beta Code but it has diacritics for both narrow and wide letters. It's also a good cross-platform solution.
Many Greek fonts use the upper ascii characters.
The problem with this is that Windows and Macintosh machines map the upper ascii characters differently. So otherwise excellent Greek fonts can easily look garbled on either Macintosh or Windows machines. So it works nicely cross-platform. Finally, it is easily available. Because it is freely available on the web, you don't have to worry about violating copyright when you use it.