The AD&D 2[sup:39bmkrfa]nd[/sup:39bmkrfa] ed. rulebook [url=
http://www.amazon.com/Demihuman-Deities ... 1:39bmkrfa]Demihuman Deities[/url:39bmkrfa] (the Eilistraee section of which you can find [url=
http://trismegist.narod.ru/de_eilistrae ... l:39bmkrfa]here[/url:39bmkrfa]) says the following:
[quote:39bmkrfa]The titles of individual priests vary widely-and at some temples are personally selected during a private Flame Song-but some common examples include Moon Dancer, Moon Singer, Dark Huntress, Argent Maid, Living Sword, Unsheathed Blade, Sword Smith, Bright Edge of Darkness, and Ghost of the Moonstruck Night.[/quote:39bmkrfa]
But an older source still (and I think one of the first articles published on Eilistraee) is the "If You Need Help--Ask the Drow!" article in Dragon Magazine #176 (a pdf of which I've found [url=
http://people.internet2.edu/~eboyd/Drmg176.pdf:39bmkrfa]here[/url:39bmkrfa]). That article is about Eilistraee's Promenade (big temple in Undermountain), introducing a lot of Eilistraeen concepts, and has the following text on Flame Songs:
[quote:39bmkrfa]This is followed by a play-and-work period in which all of the faithful do repair work, storage, food preparation, and the like until they end the cycle by taking to their beds. During this time, the Chosen make their most important prayers of the day: the personal, solitary Flame Songs.
A priestess performs a Flame Song when moved to do so, dancing around a candle or other flame. The song to the goddess is personal, taking any form desired, and ends when the flame dies. It is the height of rudeness for a priestess to deliberately interrupt the Flame Song of another; outsiders and nonbelievers are usually forgiven for their ignorance. Priestesses often try to find an alcove or passage where they can be alone to make a Flame Song. A visitor to the Promenade at this time can hear the eerily beautiful echoes of half-adozen or more of these solos at once, drifting down various passages and in side caverns and rooms.[/quote:39bmkrfa]
The description of the Flame Song in that article sounds a lot like what later became Evensong (which didn't have the candle bit). This is probably, I would guess, that for an Evensong it's usually more practical to do without a candle to dance around.
But regardless I think that gives a nice description of what a Flame Song is.
Oh, and I had to look this up too (didn't remember it either though I'm sure I've read it before), so thank you for asking.
[EDIT] I feel that there's one thing I should add here. I've always believed that there's no real standard in rituals among all Eilistraeen communities and that each community has its own variations. For example, some might perform a Flame Song as described at the end of every day, others do more of a solitary Evensong. And for others yet an Evensong might be a group activity (as described in War of the Spider Queen: Extinction). In short, a Flame Song might be exactly as described there, or it could be different depending on the community. After all, Eilistraee is a Chaotic deity so it makes sense that there are no strict rules in how rituals are to be performed.
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