Unless otherwise specified, use Shunn formatting. A Google search will bring it up (I'm at work, sorry). But 12 point, Times New Roman, double-spaced, one inch margins, no tabs is it. However, always check publisher guidelines for tweaks. The most common change is 1.5 spacing or 1.5" margins. They'll also tell you what format to use: doc, docx, pdf, rtf or txt.

Hope that helps.