It's going to be quite a list:
Tripod (ball head recommended) - essential as you will be doing long exposures. Look for a tall one as you will be pointing the camera at the sky and need to fit yourself under it. Also ensure that when mounted, the cameras' battery cover is not obstructed.
Lens - wide, fast, sharp and with minimal vignetting or what ever is within your budget or currently attached to your camera. Make sure to remove any filters, protective or otherwise, as these can produce concentric circles on your images.
Shutter Release - not essential but really useful, get a cabled release rather than a remote release as batteries freeze quickly. Alternatively use the cameras' self timer, either way you're trying to reduce camera shake when triggering the exposure.
Spare Battery - essential, you will need to keep a battery warm at all times, so a second is required unless you want to wait while warming your battery back up!
Memory Card - you can get Extreme cards that are designed to function in low temperatures but I'm not sure of the need.
Other - head lamp (get one with a red light that preserves night vision), hand warmers, wool insoles, thick soled boots, down jacket (layers are less important than insulation when standing around) non-cotton/natural under layer.
Technique:
Focus - With the camera set to single point focus and preferably using the centre focal point, pre-focus to infinity by auto-focusing on a distant object that has contrast and then switch your lens to manual and use focus lock if the lens has it or tape the focus ring to the body of the lens to prevent movement. Alternatively use Live View to focus on a bright distant object (moon or stars) when at location. Auto-focus on the object and with Live View zoomed in manually adjust until sharp.
ISO - you'll want high ISO, around 800 will be good but you may want to experiment with quality/results for your specific camera before you leave.
Shutter Speed - Bulb mode, activated with cable shutter release or camera self timer. You will have to make a decision as to how long to maintain the exposure depending on how bight the Aurora are on that night. Read up on Histograms as these will tell you how your timing is effecting each exposure.
Aperture - As wide as you can go with your lens at the focal length you are using.
Noise Reduction - if your camera has it, use it.
Format - RAW you'll want to process them and RAW contains the most information to work with. If you're not sure how to just yet then shoot in RAW + JPEG mode but keep your RAW files for later processing.
Tips:
- Always keep a battery warm;
- Remove lens filter;
- Shoot between 10PM and 2AM;
- Locate yourself far away from light pollution;
- Include some foreground interest; maybe get a flash to light up close objects (this is a whole other subject though!)
- Check your histogram
- There's an iPhone app for tracking the Aurora, although I'm not sure if it's any good.
Oh and good luck, when I went to see them I slept through the best display of the week!