Alan Brookstone in CanadianEMR points to an paper from the US based AARP that compares and contrasts approaches taken in a describing the differences and lessons learned in Canada, Australia, England and New Zealand in terms of Personal Health Records.

Of course much that is discussed is relevant as well to the question of effective use of EHRs.

You can find Alan's writings at:
http://emruser.typepad.com/canadianemr/2006/03/learning_from_a.html

The AARP report (pdf) can be found at: http://assets.aarp.org/rgcenter/health/2006_10_phr_abroad.pdf