3141card has released a PKG for multiMAN that monitors the PS3′s CPU/GPU temperature.
3141card has made a standalone pkg that allows you to view the internal temperatures of the CPU & GPU of your PS3. Once the code was released. Deank picked this code up and implemented it into multiMAN version 04.06.02 (CEX). You can now view the temperature of your CPU & GPU just as easy as checking the time in multiMAN. Great job 3141card ,Mysis, & Deank and anyone else involved. This will be of great use by many people.
Source: multiMAN Online Update
http://www.mediafire.com/?5o47j918a76j5aa – 04.06.02 Update PKG (CEX) –
http://www.mediafire.com/?z8jns9t8amxuwxi – Standalone PKG by 3141card –
Source: Ps3Hax forums
Tech. Source: PS3dev Wiki