CPU temperature between 39-58C, Is It normal?

"My work laptop has a Core 2 Duo and regularly gets up to 55C when working hard, I wouldn't consider it massively hot.

There's a temperature guide for Core 2 Processors here. It does look rather confused, but hopefully it will make sense."

"I noticed that you're using CoreTemp, and it seems that CoreTemp reports higher temps than actuals:

only with RealTemp the readings are 10
degrees lower > 30-32C idle. I think
the readings you're getting are
normal, but the actual temp is lower.

My temperatures are also ~10 degrees
higher with Core Temp than Real Temp,
and I'm hitting loads of about 50C
with Core Temp on an Ultima-90 at
3.0GHz. Way too hot to be real.

Even if those were the real temperatures, they aren't that alarming, and as Jeff mentioned, Tj. max temperatures are still quite a bit off from your temperature readouts.
FWIW The Core2Duo T5250 on my Dell Inspiron 1520 hits ~ 47 idle, ~60 on load ~80-85 on gaming, and laptop's about 2 years now and I haven't faced any problems/"