Imaging - EKG, CXR, CT scans

ECG Wave-Maven by the Harvard Medical School is a fully-fledged ECG-trainer. You can browse through typical or not so typical EKGs here. Check out the arrhythmia simulator - you can play, pause and quiz yourself. Just click "start" on the welcome screen, you do not need a user name/password. ECG Palm Brain is the best free reference for PDAs. It works on both Pocket PC and Palm, iSilo ($ 19) is required.

CXR and CT scans
University of Virginia has a comprehensive website dedicated to CXR and CT scans. Compare what you see on the screen to the CT scans of your patient. ICU CXR is another very useful website from the University of Virginia.