The Pentium M will scale down speed ('throttling') to do one of two things... Conserve power or to prevent overheating. 60C is the typical threshold for thottling. In your case, I'm betting it is overheating.
Laptops do indeed run hot (even Pentium Ms), but I think you have a valid cause for concern. If you've had the laptop for several months or longer, there's a good chance it needs to be physically cleaned out.
You see, manufacturers think they can get away with using a tiny, aluminum heatsink and a cheesy fan on Pentium Ms because they generate less heat than your average CPU. Unfortunately, this makes them more prone to environmental issues such as dust and high ambient temperatures because the cooling system is so poor.
If you feel comfortable taking apart your laptop, I would suggest removing the CPU / heatsink assembly and giving it a good cleaning. (This can actually be a pretty simple process with a lot of newer laptops).
If you're not so technically inclined, you may be able to use something like pressurized air to blast out the dust through the cooling vents on the side/bottom of the notebook. It won't work as well, but it will probably work well enough to lower your temperatures considerably. You might want to make sure it is off, just avoid any complications.
Just so you know, I've taken apart lots of laptops for this reason and they've always been satisfied afterward.
This includes my own Pentium M laptop. I lowered my temperatures by 15*C the last time I cleaned it out.