  Superconductivity in the two component model of coexisting local electron
pairs (hard-core charged bosons) and itinerant fermions coupled via charge
exchange mechanism is discussed. The cases of isotropic s-wave and anisotropic
pairing of extended s-wave and d_{x^2-y^2} symmetries are analyzed for a 2D
square lattice within the BCS-mean field approximation and the
Kosterlitz-Thouless theory. The phase diagrams and superconducting
characteristics of this induced pairing model as a function of the position of
the local pair (LP) level and the total carrier concentration are determined.
The model exhibits several types of interesting crossovers between the BCS like
behavior and that of LP's. In addition, the Uemura plots are obtained for
extended s and d_{x^2-y^2} pairing symmetries. Finally, we analyze the pairing
fluctuation effects (in 3D) within a generalized T-matrix approach. Some of our
results are discussed in connection with a two-component scenario of preformed
pairs and unpaired electrons for high temperature superconductors.
