This is a little different than the common Natty temperature applet question. I've given Unity a shot and have reverted back to Ubuntu Classic. The one thing that is still not working is the temperature panel indicator (on 2 different laptops). It reports 'No Thermal Monitor Support' and shows a big red 'X'. The temperature sensors are working as GKrellM can still report temperature properly. Does anyone have a solution?
The specific applet is the 'computertemp' applet. After Jorge asked for more details, I tried the other one, the 'sensors-applet', and it actually works correctly.
Your first port of call should be the application help page