A short and beautiful exposition of Postnikov stuff and the underlying ideas is LNM0013.
A rigorous treatment is found in Jardine-Goerss chapter VI. They also discuss model structures on towers of spaces.
http://ncatlab.org/nlab/show/Postnikov+system+in+triangulated+category
Dieudonne in Panorama: The notion of fibration also enables us to characterize homotopy types by a system of invariants. Given a sequence of groups commutative for , we define a sequence of spaces where and for is a bundle with base and fiber . The inverse limit of the sequence is such that \pi_n (X) =
G_n$ for all $n$, and every space $Y
has the same homotopy type as such an inverse limit; this homotopy type is characterized by the and, for each , the isomorphism class of the bundle with base ; it can be shown that these isomorphism classes are in one-one correspondence with cohomology classes in (Postnikov’s construction).
Dwyer: Self-homotopy equivalences of Postnikov conjugates
nLab page on Postnikov tower