It also depends on the size of your case and the quality of ventilation/fans the load your running it under and other cards you might have in your pc especially graphics cards for gaming will generate lots of heat.
I have built probably over 100 P4 pcs in my job and have found the new ones to run pretty hot. Under load many of them ran at up to around 62 degrees completely standard with the intel heatsink/fan.
Your cpu will slow down if it gets too hot. They have built in protection so if your system is stable I wouldnt worry about it too much.
If your keen how ever I would open the case and clean out all the dust the an aircompressor, just make sure you stop the fans with somthing or you can damage them.
Hope my novel helps