Device Manager reports 2 CPUs

I have a 3-month-old HP Pavilion a450n desktop computer running Windows
XP SP1.

Device Manager reports two CPUs instead of one, like this:

[machine name]
ACPI Multiprocessor PC
Microsoft ACPI-Compliant System
Intel(R) Pentium(R) 4 CPU 3.00GHz
Intel(R) Pentium(R) 4 CPU 3.00GHz

Is this a symptom of Intel's "hyperthreading," or is my machine very
confused about its own brain?

Thanks,
- Bob