None of the above worked for me on Windows 7 64-bit, but they did lead me in the right direction. The Non-Sucking Service Manager ended up being the key. Below is the code for the two .bat scripts needed to install a Perl script as a service in Windows 7 64-bit. It should also work in 32-bit versions, but I have not been able to test this yet.

install_service.bat

@echo off
if defined %ProgramFiles(x86)% (
    "%ProgramFiles(x86)%\path_to\your_app\service\nssm.exe" install my
+Service "C:\Program Files (x86)\path_to\your_app\portable_perl\perl\b
+in\perl.exe" """C:\Program Files (x86)\path_to\your_app\myService.pl"
+""
) else (
    "%ProgramFiles%\path_to\your_app\service\nssm.exe" install myServi
+ce "C:\Program Files\path_to\your_app\portable_perl\perl\bin\perl.exe
+" """C:\Program Files\path_to\your_app\myService.pl"""
)
net start myService
exit
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remove_service.bat

@echo off
net stop myService
if defined %ProgramFiles(x86)% (
    "%ProgramFiles(x86)%\path_to\your_app\service\nssm.exe" remove myS
+ervice confirm
) else (
    "%ProgramFiles%\path_to\your_app\service\nssm.exe" remove myServic
+e confirm
)
exit
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