Glad I noticed this thread. Since I'm so busy, I hardly have time to post on here, but I check out the threads often.
My 2009 MBP 15" is, too, much warmer than normal. I started up my computer about 25 minutes ago and have simply been playing around on Facebook, Twitter, and checking my blog stats. Nothing open except Firefox.
My fans are set (via SMC Fan Control) to 4,500 RPM and my temperature is still 180°F / 83°C. This is a good 30°C warmer than before Snow Leopard under the same conditions.
iStat reports:
CPU: 83°C
CPU heatsink: 62°C
All Enclosures: 32°C
GPU: 62°C
HDD: 35°C
I did upgraded, for what it's worth; no fresh install.
UPDATE: I have an idea. Try opening Activity Monitor; ensure "All Processes" are selected. Check out which process is using the highest CPU percentage. For me, it was Growl at 95%. I quit the process and shortly thereafter, my MBP returned to a normal operating temperature of around 55°C.