MedPDA.net used the newly launched PubMed feeds to get RSS for any journal. He also explains how to set up the feeds yourself in the post How-to: RSS feeds for medical journals.
JAMA and Archives Have RSS Feeds Now
General and Internal Medicine
New England Journal of Medicine: RSS
Annals of Internal Medicine: RSS
JAMA (Journal of American Medical Association): RSS
BMJ (British Medical Journal): RSS
Archives of Internal Medicine: RSS
Nature: RSS
Nature Medicine: RSS
Hematology / Oncology
Blood: RSS
Journal of Clinical Oncology: RSS
Journal of the National Cancer Institute (JNCI): RSS
Haematologica: RSS
Bone Marrow Transplantation: RSS
References:
PubMed RSS feeds are now live
Getting RSS feeds for most medical journals - MedPDA.net
How-to: RSS feeds for medical journals - MedPDA.net
Use Plucker to get Journal RSS feeds in your PDA - Palmdoc.blogspot
RSS tutorial for STFM Board. Family Medicine Notes
A really simple guide to a powerful tool: RSS. BMJ Career Focus 2006;332:244.
(Source: www.medpda.net & http://casesblog.blogspot.com/)