Found this. Could get server names in cluster, then run the last script for each node name in cluster and get the versions.

http://powershellcommunity.org/Forums/tabid/54/aft/7885/Default.aspx

Get-WmiObject sqlserviceadvancedproperty -namespace "root\Microsoft\SqlServer\ComputerManagement10" -computername $env:computername | Where {@("SKUNAME","VERSION") -contains $_.PropertyName } | SELECT __SERVER, PropertyStrValue

Works in SQLPS, will have to test at home.