Before The Shadows Fade
There are a LOT of Manga for the "Pocket Monsters" series-but hardly any of them are dubbed into English and even so, the ones that are are completely ruined by the horrible dubbing. But since I don't want to go around swiping info on the Mangas that arent dubbed, I'll only explain the dubbed ones. If you are dieing to find out about the undubbed ones, dig into Dogasu's Backpack.
Click on the Japanese Manga title to see a picture from it.

"Pokémon: Dengeki Pikachu" (English name: "Pokémon"):
"Pokémon: Dengeki Pikachu" has the same characters as the Animé version of the show and is composed of some of the episodes from the Animé-but "Pokémon: Dengeki Pikachu" puts it's OWN twist on things. What I really meant to say is that the original Japanese version of it turns the G-rated cartoon into a R-rated comic book. But the English version... the English version sucks. Everything that's interesting is edited. I wish it was never dubbed. Stupid, stupid dubbers. Stupid, stupid Ono for creating this Manga to begin with...
Pokémon Den-Geki Pikachu - The Manga - Uncensored will show you what I mean.
My Recommended Age Group:
Japanese Version - 17 and up
English Dubbed Version - 14 and up
Reasoning: First and foremost sexual-wise.

"Pokémon Special" (English name: "Pokémon Adventures"):
The dubbers ruined this Manga by not dubbing all of the volumes.
"Pokémon Special" was originally about a boy named Shuu whose dream is to fill up his Pokémon Zukan by becoming a Pokémon Trainer. After a while, the story branched out a lot.
Serebii.net has a lot of info on it.
My Recommended Age Group: 12 and up
Reasoning: The frequent monster deaths.

"PiPiPi Adventures" (English name: "Magical Pokémon Journey"):
Join Maron, Almond, Dr. Coconut, Grandpa, and all their friends on a trip through multiple love polygons and a healthy dose of randomness!
Maron is collecting as much data on Pokémon as possible for Grandpa to bribe him to make her a love potion for Almond the oblivious. Well... Grandpa put it best when he said "On the rare occation you aren't mooning over Almond!"
There isn't much to be edited so guess what the English dubbers did to kill it? Other than changing names like "Peas" to "Peanut" for no reason, they didn't dubb all of the volumes!!! However, Willow Haze is translating some of the undubbed volumes so you can sleep peacefully. ^_^
My Recommended Age Group: To be determined.
Reasoning: Nobody ever gets very hurt in the Pokémon Battles... but once Grandpa & several Pokémon get drunk... and in the Japanese version Hitokage likes to say bad words...