Tales of Innocence R and Tales of the Heroes don't really have much to do with one-another as far as Tales games go, but because they were announced at the same time and Namco Bandai keeps on providing updates at the same time, they're forever doomed to being placed together in a single story.
Today, Namco Bandai gave both games full official sites.
First up, Tales of Innocence R. Access the site here. There's not much worth seeing at present, although you can hear some voice samples from Ruca Milda. There are also a few screenshots, which may or may not be new.
Tales of the Heroes Twin Brave has a bit more content. Access the official site here for a look at the previously announced characters.
The Twin Brave site says that you fight alongside a partner character, facing off against masses of enemies. You'll be able to make use of group combos and a "partner follow" (I'm not sure what this is -- maybe just your partners being linked up to follow each other?).
The game will have 2 characters from each of 15 Tales games. Each will have an original story where they're the main character. These are presented as skits.
The official site's spec page does not say if the game will have a download version... although with Vita coming out in December and Heroes not due until 2012, damn straight there'd better be a download version!