BTW- Not super useful for most people since you can't use it while hashing since the mining software has the port open, but the ZlX command (lowercase "L") will return the temperature of all the chips. If you're compiling your own cgminer, you might want to add in a way to read that.
I found ZcX which adds the internal chip temperatures behind the processor output:
PROCESSOR 0: 9 engines @ 137 MHz -- MAP: E07E 27 C
PROCESSOR 1: 14 engines @ 198 MHz -- MAP: DFF7 26 C
PROCESSOR 2: 7 engines @ 188 MHz -- MAP: 0BF0 27 C
PROCESSOR 3: 15 engines @ 201 MHz -- MAP: FF7F 29 C
PROCESSOR 4: 13 engines @ 159 MHz -- MAP: E7FE 27 C
PROCESSOR 5: 8 engines @ 168 MHz -- MAP: 0FF0 27 C
PROCESSOR 6: 8 engines @ 179 MHz -- MAP: 0FF0 26 C
PROCESSOR 7: 15 engines @ 179 MHz -- MAP: F7FF 32 C