A quick search for windows cpu returned Determine Windows Box %CPU use.

In the interest in a comprehensive reponse, the two modules recommended were Win32::PerfLib and Win32::SystemInfo.

UPDATE: While reviewing the POD for the above modules in the interest in creating sample code, I came across the following:

Win32::SystemInfo::MemoryStatus(%mHash,[$format]);

...

MemLoad

• Windows NT 3.1 to 4.0: The percentage of approximately the last 1000 pages of physical memory that is in use.
• Windows 2000: The approximate percentage of total physical memory that is in use.

...

MemoryStatus return values in bytes by default. This can be changed with the $format parameter. Valid values for $format are:

       B        -  Bytes (default)
       KB       -  Kilobytes
       MB       -  Megabytes
       GB       -  Gigabytes

Comment on Re: monitoring CPU usage Select or Download Code