We describe recent work at NIST to develop compact, sensitive atomic magnetometers using a combination of precision optical spectroscopy, atomic physics and techniques of micro-electro-mechanical systems (MEMS). These instruments have sensor head volumes in the range of a few cubic millimeters but are capable of sensing magnetic fields of a few picotesla per root-hertz in the earthpsilas field and as weak as 70 femtotesla per root-hertz in a shielded, low-field environment. We discuss the design, fabrication and testing of several of these devices and propose several applications for which such instruments might be of use.