1) Command to get PowerShell Version:
$PSVersionTable.PSVersion
2) Command to get the current directory of the PowerShell Script:
a) In PowerShell 3.0
$PSScriptRoot
b) In PowerShell 2.0
$scriptPath = split-path -parent $MyInvocation.MyCommand.Definition
3) Read xml file into PowerShell
$xmlFilePath = "C:\SampleXmlFile.xml"
[xml]$xmlFileContents = Get-Content $xmlFilePath