Harry Potter: No matter how great your Potter-expertise, you're sure to learn a thing or two at Steve Vander Ark's definitive Harry Potter Lexicon. Enlightened and intelligent discussion from a terrific group of people is available at Harry Potter for Grownups, where most of these filks first saw light of day (or, more properly speaking, light of computer screen). Another filk-friendly discussion group meets at The Hog's Head. Keep up with all the latest doings in the Potterverse via The Leaky Cauldron, the last word in HP blogging. Harry Potter Facts offers convenient chapter summaries of Volumes 1-6. Other collections of Harry Potter filk (in addition to those listed above) can be found at Fiction Alley's Rhythm and Rhyme, Swish and Filk, Harry Potter Realm, Fronskie Feint, Harry Potter Christmas Carols, Mugglenet, Flourish and Blotts Poetry Corner, The Green Dragon, Barbara J. van Look's Order of the Phoenix musical, The Three Broomsticks, The Leaky Lounge , PhoenixSong, PatFromSwitzerland, Mirrel (featuring HP filks in Polish), Harry Potter and the Half-Blood Poet (a parody of TS Eliot's The Wasteland) by ladysisyphus and rahaeli, and FanFiction.Net (here, here, and here). If you enjoy "Wrock," you may find this listing of bands useful. Finally, we must make mention of this singularly authoritative (if too infrequently updated) site.
Filk-Casting: Swish and Filk is very attractively designed site that offers audio performances for most of their high-quality filks. Deanna Gray's filkcasts can be heard here. She is soliciting contributions from the HP filking community - get the details, and if you've the technology and talent, they would like to hear you perform your own filk songs. The Leaky Cauldron's PotterCast series occasionally offers performances of filk, as does this episode of Fiction Alley's SpellCast.
Inspirations: I was inspired to start filking after listening to the great parodies of The Capitol Steps. The clever and sophisticated songs of the recently DVD-resurrected 'toon series Animaniacs have likewise animated my work. And when it comes to the actual writing process, an indispensable resource which has time and time again provided me with the mot juste is The Rhyme Zone.
Lyrics and Songs: If you're interested in looking up original lyrics, one of my favorite catalog of pop standards is Lyrics World. Another good site (with an emphasis on more recent material) is Let's Sing It. The Collection of Musicals and SoundTrack Lyrics are the Web's most complete archive of music theatre libretti. We have also ransacked the rich resources of Disney musicals, Gilbert & Sullivan, Tom Lehrer, The Beatles and "children's" music.
Audio: The best place to find renditions of a particular song these days is YouTube. As for MIDI-based sites, HamieNET offers MIDIs of just about every filkable genre of music. Other MIDI-based sites include CCR/John Fogerty MIDI Files & Sound Clips, The Beatles' Jukebox, Sounds America, Tom Lehrer MIDIs, and Folk Music of Britain, Ireland & America. The Gilbert & Sullivan site mentioned above has extensive sonic links.
Filk: And just what is "filk," anyway? Kay Shapero provides the answer. A listing of filk sites is offered at Darn Near All the Filk on the Web. Be sure to check out the links to Tolkien filks.