ICUfaqs is a GREAT source. I know it seems like a lot of is tailored towards the author's own place of employment, but it is a goldmine of information if you take the time to read through it.
For medications, know your vasoactive medications - levophed, epinephrine, dopamine, dobutamine, neosynephrine, sodium nitroprusside, nitro. Other drips to know - cardizem, amiodorone, integrillin, heparin, lasix, bumex, octreotide, propofol, versed, fentanyl. All other meds are fair game, but those drips are typically the ones you encounter in ICU (some in step down) and not anywhere else in the hospital.
Nursing skills - excellent assessment skills (and that develops over time), managing chest tubes and other drains, managing mechanical ventilators, hemodynamic monitoring, arrhythmia interpretation, ICP monitoring, assisting with central line/chest tube insertion, management of NG tubes/Dobhoffs/G-tubes, tube feeding, TPN, IABPs (if your unit has those types of patients), pacemakers, transcutaneous pacing/DC cardioversion/defibrillation...the list goes on an on.