MedWorm! What a nice surprise discovery! MedWorm is a RSS feed provider which daily collects updates from (at the moment) over
3500 4000 medical data sources (medical blogs and web sites, medical journals).
You can then subscribe (e.g., by using Google Reader) to its outgoing RSS feeds which are conveniently diveded into a number of medical categories (see here for a list of blogs and here for a list of article categories).
(And even better — MedWorm’s database is searchable.)