I use speedfan to monitor the temps, is a good software to do this or can you recommend something better?
Btw i'm getting 32°C idle on my gtx 470 on air cooling is this good?
32 idle is fine, you should only really need to worry about how hot it gets on load; Also personally I prefer CPUID's HWMonitor as it provides a more detailed indepth view of system temps & power usage.
The idle temp of your GPU is good, but if you run HWMonitor as Gishank says it gives you Current Temp, Minimum Temp, Maximum Temp. So if you load HWMonitor before playing a game for example, you will see what the max. temp it hit under load