  The achievement in cooling alkali atomic gases, such as $^{87}$Rb, $^{23}$Na
and $^{7}$Li, to quantum degeneracy opens up a way to study magnetism in spinor
bosons, because these constituent atoms usually have a hyperfine spin degree of
freedom. This article reviews several basic problems related to the
ferromagnetic phase transition in spinor atomic Bose gases from a theoretical
perspective. After a brief discussion on various possible origins of the
ferromagnetic interaction, the phase diagram of the ferromagnetically coupled
spinor bosons is investigated. It is found that the ferromagnetic transition
occurs always above Bose-Einstein condensation and the Bose condensate is fully
polarized. The low-lying collective excitations of the spinor condensate,
including spin and density modes, are discussed. The spectrum of the density
mode is of the Bogliubov form and the spin wave spectrum has a $k^2$-formed
dispersion relation at long wavelengths. The spin-wave stiffness coefficient
contains contribut
