I found a chart on Gotmead.com that shows you what temps and how long you will need to keep it at that temp to pasteurize.
Temperature (°F/°C) ---- Time (minutes)
123/51 ----- 470
130/55 ----- 170
135/57 ------ 60
140/60 ------ 22
145/63 ----- 7.5
150/66 ----- 2.8**
155/68 ----- 1.0**
** Extrapolated from logarithmic curve constructed from Townsend's data.
I will tell you this though. I was thinking the shorter time that it was on the heat the better and realized that by the time i had gotten it to 145 it had already ben on the stove for 20 minutes. By the time it had gotten to 150 it had been on the stove for 22 minutes. I took it off one minute after it reached 150. Icebathed it immediately. While it was coming down in temp it was still pasteurizing.
I watched a guy (on of the guys in charge of brewtribe.com) make a mead at our club barbecue. He didn't pasteurize the honey at all. He of course was not using raw honey.