Check this page
for the announcment or continue reading if you're lazy.
From Rainbow Studios, the makers of MX Unleashed [XB & PS2], the Motocross Madness PC games, and the frirst two ATV Offroad Fury [PS2] games comes an all-out offroad extravaganza! Ok, that was my wording, but it's got all sorts of off-road sports vehicles. Everything from motocross dirtbikes, ATVs, sand-rail cars and 4x4 golf carts as well as the return of the monster truck and bi-plane from MX Unleashed.
No word on online support, but I'm sure as hell hoping it has it!