I'm not sure if this is everywhere, but last weekend I got a great deal at Waldenbooks. The store was closing down and they had a huge sale on manga and I got the entire Red/Blue series of Pokémon Adventures, a Best of Red and Best of Yellow book, and a manga adaptation of the Manaphy and Giratina movies. It only cost me $22! If you have a Waldenbooks near you I'd suggest you check it out for youself if you like manga. The pokémon mangas are hard to find these days.
The Pokémon Adventures (PA) series is pretty good in my opinion. Most pokémon comics, like the Electic Tale of Pikachu ones, follow Ash alot like the tv show and so do the movie adaptations. PA follows the main characters of the games: Red, Blue, Yellow, etc. Sure it's wierd that all of the main characters are named after colors, but that's how it's done in the games too. Look at HeartGold and SoulSilver when it comes out. You'll have to face Red at the end of the game.
Anyway, if you want to read them, Manga Fox has them availible online and I suggest you check them out. You may like them. So far I'm at Ruby/Sapphire.