(For those who didn't catch the reference, "__________ For Dummies" is a series of how-to books and it isn't intended as an insult)

I thought this might be useful for those that are either unfamiliar with Sonic X or are confused about when each story takes place.

I'll edit the topic as new info becomes available. This topic is current as of 4 March 2006

UPDATE 30 DECEMBER:

I TOTALLY redid this, with nifty tables and everything, and that took a while. But it won't post correctly because of Knothole forum's strangeness. Anyway, I've updated the titles and links for the current version. You can expect to see the table-heavy version after the move.

NEW WORLD SAGA

001 - Enter the Super Sonic Hedgehog! (US: Chaos Control Freaks)
002 - Infiltrate Area 99 (US: Sonic to the Rescue)
003 - Dr. Eggmans Ambition (US: Missile Wrist Rampage)
004 - Get the Chaos Emerald! (US: Chaos Emerald Chaos)
005 - Clash!! Sonic VS Knuckles (US: Cracking Knuckles)
006 - Fierce Battle! School Wars (US: Techno Teacher)
007 - Giant Free For All! Chris House Party (US: Party Hardly)
008 - Emergency Launch! X Tornado (US: Super Sweeper)
009 - Amy on the Beach (US: The Last Resort)
010 - Fierce Fight! Sonic Baseball Team (US: Unfair Ball)
011 - The Beautiful, Mysterious Thief Rouge Arrives (US: Fly Spy)
012 - Before the Attack on Eggmans Base (US: Beating Eggman, Part 1)
013 - After the Attack on Eggmans Base (US: Beating Eggman, Part 2)

Sonic, Tails, Knuckles, Amy, Cream, Rouge, Eggman, Decoe, Bocoe, and Bokkun enter Chris's world through Chaos Control. Lots of exposition occurs.

CHAOS EMERALD SAGA

014 - Chase After the Hero Sonic! (US: That's What Friends Are For)
015 - The Mobile Fortress Attacks (US: Skirmish in the Sky)
016 - Shoot for the Sunken Ship in the South Sea (US: Depths of Danger)
017 - Knuckles! Clenched Fists of Anger (US: The Adventures of Knuckles and Hawk)
018 - Huge Shoot-out on the Savannah (US: The Dam Scam)
019 - The Ghost of King Boom Boo in the Old Castle (US: Sonic's Scream Test)
020 - Combat Mission! Egg Fort II (US: Cruise Blues)
021 - Speed Match! Sonic VS Sam (US: Fast Friends)
022 - Summer Vacation Chao Observation Diary (US: Little Chaos Lost)
023 - Mayhem! 6 Chaos Emeralds (US: Emerald Anniversary)
024 - Sonics Running Wild! Capture Him! (US: How to Catch a Hedgehog)
025 - The Last Chaos Emerald (US: A Dastardly Deed)
026 - The Birth of Super Sonic (US: Countdown to Chaos)

A mad scramble to assemble all the Chaos Emeralds and go back home. Once all the Emeralds are gathered, Chaos Control occurs, but instead of sending Sonic and company home, it brings parts of Sonic's world (Mystic Ruins, Angel Island, etc) into Chris's world.

CHAOS SAGA

027 - The Beginning of Disaster (US: Pure Chaos)
028 - The Puzzle of the Liquid Life Form, Chaos (US: A Chaotic Day)
029 - Amy the Captive (US: A Robot Rebels)
030 - Egg Carrier Battle (US: Heads Up, Tails!)
031 - Gamma the Wanderer (US: Revenge of the Robot)
032 - The Cry of Perfect Chaos (US: Flood Fight)

A few months after the events of episode 026, the events detailed in Sonic Adventure occur.

Sonic X #1 - Savings and Groan
Sonic X #2 - See Sonic! Sea Battle! See Sonic Sea Battle!
Sonic X #3 - Field Trip of Doom
Sonic X #4 - Boisterous Bot Battle!
Sonic X #5 - I Never Promised You a Chao Garden: Part One
Sonic X #6 - I Never Promised You a Chao Garden: Part Two
Sonic X #7 - Take This Job and Shovel It
Sonic X #8 - Wicked Sweet Shuttle Shenanigans: Part One
Sonic X #9 - Wicked Sweet Shuttle Shenanigans: Part Two

SHADOW SAGA

033 - The Mystery of Project Shadow (US: Project: Shadow)
034 - Sonic the Fugitive (US: Shadow Knows)
035 - Escape From Prison Island (US: Sonic's Big Break)
036 - Threat From Outer Space (US: Shadow World)
037 - Space Colony ARK Battle (US: Robotnik's Revenge)
038 - Marias Request, Everyones Request (US: Showdown in Space)
039 - The Chaotix Detective Agency (US: Defective Detectives)

Sonic Adventure 2 adaptation, and then a story involving the Chaotix and Cream's reunion with her mother.

Sonic X #10 - No Thanks for the Memories: Part One
Sonic X #11 - No Thanks for the Memories: Part Two

EGGMOON SAGA

040 - Eggman Corporation (US: Sunblock Solution)
041 - We Can See the Light! (US: Eggman for President)

Eggmoon story. Eggman, turned "good" during SA2, runs a scam and is exposed as the evil guy he is. He goes to prison.

Sonic X #12 - Attack from Area 99
Sonic X #13 - Hare-Um Scare-Um: Part One
Sonic X #14 - Hare-Um Scare-Um: Part Two

SONIC BATTLE SAGA

042 - Amy, Loves Escape Journey?! (US: A Date to Forget)
043 - Huge Home Electronics Panic! (US: Mean Machies)
044 - The Ridiculous Epic Spy Battle (US: The Sewer Search)
Sonic X #15 - Bad Eggnog
045 - Sonic Battle - Face Off!! (US: Prize Fights)
046 - Sonic Battle - Finale!! (US: A Wild Win)

Some filler, during which Emerl is introduced. Then, a (rather loose) Sonic Battle adaptation.

FINAL SAGA

047 - Decisive Battle on the Equator!! (US: Map of Mayhem)
048 - Sonic VS Monster from the Underground (US: The Volcanic Venture)
049 - The Day the Earth Stood Still (US: The Beginning of the End)
050 - Morning of Farewells (US: Running Out of Time)
051 - Chris' Long Journey (US: Friends 'Til the End)
052 - Memories of the Wind (US: A New Start)

End of the first series, Sonic's World and Chris's world part. In Sonic's world, six months pass after this. In Chris's, six YEARS pass. Joe has said he may explore this gap.

METAREX SAGA

053 - A Messenger from Meteor Shower (US: A Cosmic Call)
054 - Typhoon's Take Off! (US: Cosmic Crisis)
055 - The Water Planet, Hydoo (US: H2Woah)
056 - Eggman Enters into the War! (US: An Enemy in Need)
057 - The Battle of Icepalace! (US: A Chilling Discovery)
058 - Young Girl's Jungle Trap (US: Desperately Seeking Sonic)
059 - Chaotix Goes Into Space (US: Galactic Gumshoes)
060 - Shadow Has Returned?! (US: Trick Sand)
061 - The Vessel of Evil (US: Ship of Doom)
062 - The Underground Secret (US: An Underground Odyssey)
063 - The Base of Metarex (US: Station Break-In)
064 - Sonic VS Shadow (US: A Metarex Melee)
065 - Celebration Aboard the Typhoon (US: Mission: Match Up)
066 - Critical Situation (US: Clash in the Cloister)
067 - The Black Trap (US: Teasing Time)
068 - Molly's Dream (US: A Revolutionary Tale)
069 - Planet Marmolim (US: A Planet of Misfortune)
070 - The Fatal Swirl (US: Terror on the Typhoon)
071 - An Incredible Blow (US: Hedgehog Hunt)
072 - Who Are the Metarex?
073 - Shadow's Arrival?
074 - The Lost Planet
075 - The Day of the Plantations
076 - Concerns for Sonic
077 - Cosmo's Work
078 - Rebirth of Planets

Metarex and Cosmo saga. No spoilers here.

That's all the info for for now!