You can easily gain access to the performance counters and their meaning by launching Perfmon.exe
By default, Perfmon.exe under XP gives you three bottlenecks to observe, Memory pages per second, Disk average queue length, and percent processor time.
Clicking the + near the top of the page gives you performance objects (like processor, or memory) and specific counters that you can select and add to the graph. Choose one and click the 'Explain' button. The 'Explain' window opens, and gives information about what is monitored.
Typeperf.exe -q extracts counters from the same place that perfmon.exe does. For instance, in perfmon.exe, object processor and counter % processor time translate into this counter in typeperf.exe:
typeperf.exe "\Processor(*)\% Processor Time"
The asterix means 'all counters', and typerf will give you each numbers for instance and a total (think of a two processor computer).
If you have the rights, and are connected, you can specify a remote computer, using a unc:
typeperf.exe "\\mycomputer\Processor(*)\% Processor Time"
Remember to use quotes around counters with spaces.