Scanlation Groups

This isn't a comprehensive list, they're just ones that I end up reading from that haven't closed down yet (*sniff*)

General

Aerie: shoujo, ddl
Akatsuki Manga: shounen, ddl
Aku-Tenshi: shoujo, shounen, shounen-ai, ddl, bt
Amber Love PJ: ddl, bt, text
Anime Theatre
Anime Waves: mostly shounen, bt
AtoZ: shoujo

Bad Egg: shoujo, ddl
Be With You Scans: CLAMP, shoujo, ddl, bt
Boku-Tachi: shounen, Full Metal Panic, ddl

CLAMP no Lumiere: CLAMP, ddl
Condensation: shoujo, ddl

Da Gurlz Translations: shoujo, bt, online, ddl
Dragon Voice: shoujo, ddl

Emerald Eyes: Minekura Kazuya, ddl
Entropy: mostly shoujo, ddl
Ephemeral Dreams: shoujo
Eternal-Blue: shounen, shoujo

FET: Prince of Tennis

HMR (dead): shoujo, mostly Korean, ddl
Hikari no Kiseki: cute
Hikaru no Go: shounen
Himawari: shoujo, Hiwatari Saki, ddl

Ivyscan: shoujo, ddl

JanimeS: shoujo, historical and fantasical drama, online
JanKenPon: shounen, shoujo
Jinmen Juushin: shounen, ddl

Kagami: shoujo, ddl
Kefi: shounen, shoujo, online, ddl
Korean Manwha: shoujo, mostly Korean
Kotonoha: shounen, bt

Lavendar Tinted: shoujo, text

MangaArt: shoujo
Manga Downloads: shounen, ddl, hosted ddls, bt
Manga Project: shounen, shoujo
Mangascreener: mostly shounen, bt
MegKF: shoujo, yaoi, ddl
Miracle Manhwa: shoujo, Korean
Missa: mostly shoujo, ddl

Omanga: mostly shounen, ddl, text

Perfect Illusions: shoujo, ddl
Perpetual Dreams: shoujo
Possible Soup: shoujo, yaoi, ddl, bt

Sakura-Crisis (dead): shoujo, Yuki Kaori, yaoi, ddl
SCPocky: shoujo, cute, ddl
Selene Scans: shoujo
ShoujoMagic: shoujo, smut
Smexy Bastards: yaoi
Starry Heaven: shoujo
Storm in Heaven: shoujo, yaoi, seinen, ddl
Sugar Oasis: shoujo
Sweet Lunacy: shoujo, yaoi, ddl
Syuura: shoujo, ddl

TOWNL: shounen, ddl, text
The Sylphs: shoujo, ddl, text
Toriyama's World: mostly shounen, bt
TrapNest: shoujo, mostly Korean, online
Tsubasa: ddl
Tsuzuki Jinsei o: online, ddl

Watase's Sorai: Watase Yuu, shoujo, ddl
We, the Fans (dead): shounen, ddl

Mostly Yaoi

Since this is yaoi, all of the following sites have a BL warning.

Biblos Eros: ddl
Bitter Sweet: ddl
BLiss: ddl
DokiDoki: ddl
Dork Love Scans: Bleach IchiIshi doujinshi, online
Essence of Purity: ddl
Forever More
Game Over or Continue: ddl
Hochuuami: bt, ddl
Lamplighter: Prince of Tennis ZukaFuji doujinshi, ddl
Mangagedon: ddl
Memory For You: bt, ddl
Minkyleigh: Prince of Tennis doujinshi, online, ddl
mochi*mochi (closed): ddl
Nakama
Neoterica: ddl (current projects all licensed)
Obsession
Peccatore Sanctuary
Shi-ran (dead): yaoi
Tenipuri DSP: Prince of Tennis doujinshi, ddl
YAOIness.NET: ddl
Desperate Love: ddl

Note: Ukepile has torrents for manga and BL doujinshi scanlated by Sakura-Crisis and Dragonfly (Hochuuami's doujin division).