I'm doing the polar half marathon for the first time as well. Have already registered for Jan 2013. I'm a newbie runner (have only been running for 6 months) so following a 6 months half marathon training programme which, hopefully, will get me prepared on time for the race. My aim is simple - jut to finish it within the allowed 2.5hrs.
Have been to the arctic many times before but not for sport activities. Taking Steve C's advice on expecting milder winter conditions. I was in Tromso in Feb last year and it was cold, raining, a bit of slush on the streets - just like a typical British winter evening. Looking at the pics from the previous polar half marathons it doesn't seem to be something requiring specialised arctic gear but I'll be getting a pair of those icebugs....just in case.