There are few english language
Boogiepop Phantom sites.
Here are those that I have found.
This is an excellent site. Mainly of interest because of its description of the novels as well as the live action movie. The webmaster is also interested in creating a subtitled version of the Boogiepop live action movie.
John's Boogiepop Phantom Shrine
Recently updated for the last time. Merits a visit as it has portions of Ogata's art book available.
Oldest english language Boogiepop site. Has not been updated in a good long while.
Another Boogiepop timeline, in-depth and relatively accurate.
A Boogiepop novel translation project. Not much yet, but there is hope.
Translation of the Boogiepop in the Mirror prologue.
Translation
,
and yet another translation
These are probably Boogiepop fanfics.
A small Boogiepop fan community.
A Thematic Analysis of Boogiepop Phantom
Good reading.