  We consider dual frames generated by actions of countable discrete groups on
a Hilbert space. Module frames in a class of modules over a group algebra are
shown to coincide with a class of ordinary frames in a representation of the
group. This has applications to shift-invariant spaces and wavelet theory. One
of the main findings in this paper is that whenever a shift-invariant sub space
in L2(Rn) has compactly supported dual frame generators then it also has
compactly supported bi-orthogonal generators. The crucial part in the proof is
a theorem by Swan that states that every finitely generated projective module
over the Laurent polynomials in n variables is free.
