Not sure if the community is aware yet, but the latest version of APC PCNS, v3.0.0 is now free. Albeit you need to have a supported Management Card installed in the UPS to use it. It has a release date of 19may2011.
You can install PowerChute Network Shutdown (PCNS) with Single-, Redundant. References to virtualization software include VMware? With all supported operating systems except HP-UX, AIX, and Mac OS X, PCNS. APC: Default Authentication Phrase for PowerChute Network Shutdown (PCNS). The administrator authentication phrase used by PowerChute Network Shutdown (PCNS) should be the same as that used in the NMC. The default used by the NMC is: admin user phrase. Mac OS X Server Caching; VMware Certified Professional on vSphere 5 (VCP 510 / VCP5.
I already had v2.4.4 installed on a ESX 4.1 box and it ran without issues and did shutdown the guests when your configuration in VMware is correct.
The upgrade procedure went smoothly and I didn't loose any of my previous settings.
There is a cavet, as the version of Java has changed. The release notes say to remove the old version of java before doing a update or the new version of java won't be installed. I just stopped the PowerChute Service, renamed the folder for the jre installed, then ran install script for PCNS 3. It detected the previous version of PCNS and updated everything and installed the new version of java.
You can grab PCNS v3 here http://www.apc.com/tools/download/software_comp.cfm?sw_sku=SFPCNS300&id=127&family=127&part_num=SFPCNS300&swfam=&tsk=
Good Luck Guys.
Greg