Holy shit,
leaked info. Unconfirmed, but the source previously leaked info on the Sonic Adventure port to XBLA, so they've got that going for them.
It will be called "Sonic 4" (somewhat plausable, given that 1Up said that is the internal development name)... "Episode 1". It will be the first in a series of games. It will be downloadable for the XBox and PS3 only. Despite the episodic nature, the sources say that the game will be a traditional-length Sonic title (7 Emeralds to collect, with the Zone names "Splash Hill" and "E.G.G. Station"). Fan speculation compares this to the situation of Sonic 3 & Knuckles, which was originally one long game that got broken up into two parts.
Despite only owning a Wii, this sort of news excites me, and I can't wait to hear more... if it's true.