Get-Command is your primary tool when you need to find a command to accomplish something.
You can search for verbs and/or nouns like this:
# find all cmdlets/functions that stop things Get-Command -Verb Stop # find all cmdlets/functions that affect services Get-Command -Noun Service
Beginning in PowerShell 3.0, Get-Command can also find cmdlets or functions with a given parameter:
# new in PS3 and better # find all cmdlets/functions with a -ComputerName parameter Get-Command -ParameterName ComputerName
Note that Get-Command searches the loaded cmdlets/functions. Make sure you imported the modules that you want to be covered before you start your search.