Franz's reference reminded me that there is an entire school (Universite Bordeaux I?) of people who study relations between elliptic curves, rings of integers and Galois module structure. It happens that I have hung out a bit with some of these people, but so far they haven't passed on their deep knowledge of this subject (or even their Francophoneness) to me. Nevertheless I found the following interesting paper of Cassou-Noguès and Taylor which came out soon after their book:
Cassou-Noguès, Ph.(F-BORD); Taylor, M. J.(4-UMIST) A note on elliptic curves and the monogeneity of rings of integers. J. London Math. Soc. (2) 37 (1988), no. 1, 63--72.
http://jlms.oxfordjournals.org.proxy-remote.galib.uga.edu/cgi/reprint/s2-37/1/63
I recommend especially the very well written introduction to this paper. It contains the intriguing sentence:
"These results have led us to believe that the rings of integers of all ray class fields of K are monogenic over the ring of integers of the Hilbert class field of K."