http://lifeinthefastlane.com/ The home of FOAM (Free Open Access Medical Education (#FOAMed on Twitter)). Lots of good blog posts and a great place to go to find links to everything emergency medicine.
http://emcrit.org/ The cutting edge of ED critical care.
http://www.emrap.org/ An excellent podcast on all things emergency medicine. Listen to this every month and you will know you are up to date. Expensive. Hopefully your department has a subscription they can share with you.
Blue Book (General Medicine online guidelines from Christchurch Hospital)
MD on Call. A great phone app for your first few months on the job.
Palm EM: App for your phone, iPad or tablet. A great app with lots of excellent calculators for drug doses, tube sizes and an approach to many diseases. Not so good for undifferentiated case.
Pedistat: Great paediatric resource. Get it! US$ 3.
Paediatric drug dose calculator (online, Starship Children’s Hospital)
Paediatric clinical guidelines (Starship Children’s Hospital)
Toxinz (toxicology) (Password required)
UpToDate is great if you have access to it through your institution.
eMedicine is pretty good. Sometimes it is a bit clunky as they try to fit everything into the same format.
And, of course, Dr Google knows everything 🙂