The latest Nintendo Power magazine has lots of information about the Wii version of Dead Rising, but not all of it is good. To get the bad out of the way, the protagonist (Frank West) has somehow lost the ability to jump and carry an arsenal of destructive items. Instead players will have to keep their feet flat on the ground and carry only one weapon at a time. More inside..
On the plus side, a lot of the flaws from the original have been removed. There will be no more time limits, access to multiple save files and it is now impossible to accidently kill any survivors (or is that a bad thing?). Nintendo powers comments are below

Quote from the latest Nintendo Power: ""For better or for worse, the Wii version of Dead Rising offers a fundamentally different experience from is Xbox 360 predecessor. Granted, the overall structure of the game remains the same- as freelance photojournalist Frank West, you run around a mall killing zombies while trying to get a scoop on why the dead have suddenly risen. But a number of significant structural and gameplay changes drastically alter Dead Rising's identity. On the one hand, many of the annoyances some players identified in the original game are gone. there are no more time limits, you're not restricted to a single save file, and since your attacks no longer hurt survivors, you don't have to worry about accidentally killing them during one of the games frequent escort missions. On the other hand, there are far fewer items strewn throughout the mall with which to bludgeon zombies, and you can now carry only one melee weapon at a time. A much great emphasis is placed on firearms and collecting ammunition, making the whole affair feel less visceral. Perhaps the strangest difference, though, is Frank can no longer jump. We'll see if Dead Rising still lives up to its billing as ""zombie paradise action"" when we review the game in a future issue.""

Source: Capcom Unity