I wondered about this, Dobson says no:

A prominent and powerful evangelical Christian leader, James Dobson, said yesterday that the Mormon faith practiced by Governor Romney of Massachusetts could pose a serious obstacle if Mr. Romney makes a bid for the Republican presidential nomination in 2008.

“I don’t believe that conservative Christians in large numbers will vote for a Mormon but that remains to be seen, I guess,” Mr. Dobson said on a syndicated radio program hosted by a conservative commentator, Laura Ingraham.

But Falwell says yes:

While some Christians have denounced Mormonism as a heretical sect, not all conservative Christians agree that Mr. Romney’s faith will hurt him with the religious right.

“If he’s pro-life, pro-family, I don’t think he’ll have any problem getting the support of evangelical Christians,” a founder of the Moral Majority, Rev. Jerry Falwell, told the Clarion-Ledger of Jackson, Mo. earlier this year.