The promo pic (there's a link in the thread) shows Agumon, but that doesn't necessarily mean anything.
Rumors were flying around that the show would be a sequel to Tamers (Season 3) but this is not confirmed, and it generally considered unlikely. Tamers was actually a bomb in Japan, who found it too dark, which is why Frontier went in a lighter direction to try and save the franchise.
Plot Information (Episode 1 Summary) (Slightly modified by me to use the dub terms, which I tend to prefer)
A young boy who enjoys fighting even more than the 3rd serving of rice - Masaru Daimon. On a certain day, before a fight that Masaru had been training for, a strange dinosaur-like creature appears. This strange creature, "Agumon", is a "Digital Monster" from another world, the "Digital World". Masaru and Agumon agree to communicate by fighting. However, Agumon had escaped from and was being chased by an organization which investigates digital phenomena, called "DATS (pronounced 'dats')". DATS attempts to recover Agumon from Masaru. As Masaru and Agumon are chased, they run into the Adult stage Digimon, Kokatorimon. Seeing its enmormouse form ignites Masaru's combative heart, and he challenges Kokatorimon to a fight. Upon striking Kokatorimon, a "Digisoul" forms in Masaru's fist. When Agumon recieves Masaru's Digisoul, he evolves into Geo Greymon and defeats Kokatorimon. Commander Satsuma of DATS, after reviewing the events around Agumon and Masaru, formally appoints them as scouts for DATS. Thus, the captain of the school's fight club, Masaru Daimon, and his partner Agumon, join the fight against the Digimon which are threatening the world's borders.
(A promo ran on Japanese TV last week that features Masaru actually slugging Kokatorimon. I dunno, maybe the giant chicken was peeping his girlfriend's shower or something)
Masaru Daimon Junior high student who likes to fight better than the 3rd serving of rice. When he meets someone that looks strong, he can't help but challenge them to a fight. After meeting and defeating the Digimon "Agumon" in a fight on a certain day, Agumon becomes his partner. Because of his latent powers which allowed Agumon to evolve, he becomes a member of DATS.
(The gogglehead. Except he doesn't wear goggles--the Digimon community has been scandalized by this)
Tohma H. Norstein The 14 year old child genius who has graduated university. His ability is considered elite, even within DATS. He bases his operates on data and theoretical principals, and as such, his personality clashes with Daimon's. His mother is Japanese and his father is a prominent Australian aristocrat.
Yoshino Fujieda The crimson point of Masaru's team. She acts like a big sister to Masaru and Tohma. She is shrewdly respectful, she considers it her job to push Masaru and Tohma, her ability level is very high, and she has a strong trust for her companions. Her favorite phrase is "palanquin set with jewels" (a woman who marries into wealth).
(Heh heh...and she's actually 18 years old, which means the inevitable hentai is just so slightly less creepy. She's legal.)
Agumon (Masaru's Partner Digimon) He adores Masaru, after being defeated in a fight by him while escaping from DATS. He follows and acts like Masaru, as if he was an older brother. His special technique, "Pepper Breath" is to spit flames from his mouth, and he can evolve into GeoGreymon by recieving Masaru's "Digisoul".
Gaomon (Tohma H. Norshtein's Partner Digimon) Tohma's partner who calls him "master" and follows him without question. An Elite Digimon, like his Partner, Gaomon is both cool and intellectual, end he evolves into Gaogamon.
Lalamon (Yoshino's Partner Digimon) The Plant Type Digimon that is Yoshino's partner. Special technique is Nut Shoot. Thanks to Yoshino, it excels at relationships between man and Digimon, and is reliable and tied closely to friends. Evolves into "Sunflowmon".
(Nut Shoot? My god...they've actually come up with a technique that sounds scarier than Woodmon's Woody Smasher.)
While I haven't done new Codex pages for the completely new Digimon yet, I have added the three Savers Tamers to the Profile page.
The iC didn't have seperate Fresh levels for Wanyamon and Badomon, having them all evolve out of Botamon, but that's unprecedented--I'm not going to consider Botamon their "true" Fresh form until I see it on TV.
Rosemon was originally created as the Mega for Mimi Tachikawa in Season 1, but not used. It's an interesting touch, as Daimon's partner starts familiar and branches off, while Yoshino's starts new and ends with a familiar Mega (albeit one that never made it on TV before.)
There is still no official news of an American dub of Season 5; there have been unsubstantiated rumors of it coming in 2007, though in previous seasons they didn't wait that long.
And due to the fact that Disney now owns what used to be Saban, if Season 5 is dubbed, it would probably first air on ABC Family or Toon Disney--though the most high profile move would be to put it on ABC Saturday Morning (which now shows Digimon's former Saban roomate, the Power Rangers)