  We prove that proper pseudo-holomorphic maps between strictly pseudoconvex
regions in almost complex manifolds extend to the boundary. The key point is
that the Jacobian is far from zero near the boundary, and the proof is mainly
based on an almost complex analogue of the scaling method. We also establish a
link between the regularity of the extension and the regularity of the almost
complex structures, and we determine explicit estimates for the H\"olderian
norms. As a corollary, we get in the smooth case a necessary and sufficient
condition on the almost complex structure of the target's space for the smooth
extension of proper pseudo-holomorphic maps.
