Recently the Belle collaboration discovered two resonances, Zb(10610) and Zb(10650), that lie very close to the B\bar{B}^* and B^*\bar{B}^* thresholds, respectively. It is natural to suppose that these are molecular states of bottom and anti-bottom mesons. Under this assumption, we introduce an effective field theory for the Zb(10610) and Zb(10650), as well as similar unobserved states that are expected on the basis of heavy quark spin symmetry. The molecules are assumed to arise from short-range interactions that respect heavy quark spin symmetry. We use the theory to calculate line shapes in the vicinity of B^{(*)}\bar{B}^{(*)} thresholds as well as two-body decay rates of the new bottom meson bound states. We derive new heavy quark spin symmetry predictions for the parameters appearing in the line shapes as well as the total and partial widths of the states.