Keep in mind a couple things about EA 1.) They've been horrible about delaying releases. I wouldn't expect anything to actually release in December. 2.) They seem to be taking a softer stance on price. I wouldn't be suprised to see them mimic Gameloft's pricing ($4.99 or $6.99 vs. $9.99).
Dead Space 2 was actually confirmed/announced by EA at their gaming event in Tokyo. They said it would be released December 2010, although it wouldn't surprise me if it gets pushed back into 2011. http://uk.wireless.ign.com/articles/112/1128091p1.html
No, it will be 4.99. Take it to the bank. It will not be comparable content-wise to it's console counterpart, granted, but it be 4.99, guarenteed.