http://go.vertigion.com/PowerShell-Get-CompByUser

Get-CompByUser.ps1

<#
.SYNOPSIS
Get Computers by Last Logged on User via SCCM.
.DESCRIPTION
Queries SCCM for the list of computer’s whose last logged on user matches the supplied SamAccountName.
.PARAMETER SamAccountName
For users, this is typically their EUID.  Non-user accounts may vary.
.PARAMETER SiteName
SCCM Server Site Name.
.PARAMETER SCCMServer
SCCM Server Name.
.PARAMETER SCCM_SystemOUName
Default OU Name where your Computers are stored in the AD.
.PARAMETER PassThru
Quiet Mode.  Silence all Write-Host output.
.INPUTS
System.String SamAccountName
.OUTPUTS
List of Computer Names.
.EXAMPLE
Get-CompByUser user0123
SamAccountName:  user0123
 
Name
----
Computer0123A
Computer0123B
.EXAMPLE
Get-CompByUser @('user0123','user0456','user0789')
SamAccountName:  user0123
 
Name
----
Computer0123A
Computer0123B
SamAccountName:  user0456
SamAccountName:  user0789
Computer0789A
.EXAMPLE
Get-ADUser user0123 | Get-CompByUser
SamAccountName:  user0123
 
Name
----
Computer0123A
Computer0123B
.EXAMPLE
Get-CompByUser @('user0123','user0456','user0789') -PassThru | Measure-Object
 
Count    : 3
Average  :
Sum      :
Maximum  :
Minimum  :
Property :
.NOTES
Starting point gleaned from:  <a href="http://bit.ly/AliSQt">http://bit.ly/AliSQt</a>
.LINK
http://go.vertigion.com/PowerShell-Get-CompByUser
#>
function Get-CompByUser {
    param(
        [Alias("SamAccountName")]
        [parameter(
            Position = 0,
            Mandatory = $true,
            ValueFromPipeline = $true,
            ValueFromPipelineByPropertyName = $true,
            HelpMessage = "Enter the SamAccountName of a user account."
        )]
        $SamAccountNames
        ,
        [string]$SiteName="V01",
        [string]$SCCMServer="sccm.vertigion.com",
        [string]$SCCM_SystemOUName="VERTIGION.COM/COMPUTERS",
        [switch]$PassThru
    )
     
    Begin {
        [string] $SCCMNameSpace="root\sms\site_$SiteName"
        [int] $compCount = 0
        [int] $userCount = 0
        [int] $userUknCount = 0
         
        function _checkSCCM {
            param(
                [parameter(Mandatory = $true)]
                $SamAccountName
            )
            if (Get-ADUser -Filter{SamAccountName -eq $SamAccountName}) {
                if (!$PassThru.isPresent) { Write-Host -ForegroundColor green "SamAccountName:  $SamAccountName" }
                $userCount++
                Set-Variable -Scope 1 -Name userCount -Value $userCount
            } else {
                if (!$PassThru.isPresent) { Write-Host -ForegroundColor red "SamAccountName:  $SamAccountName" }
                $userUknCount++
                Set-Variable -Scope 1 -Name userUknCount -Value $userUknCount
            }
            $computers = Get-WmiObject -namespace $SCCMNameSpace -computer $SCCMServer -query "select SMS_R_System.Name, SMS_R_System.SystemOUName from  SMS_R_System where SMS_R_System.LastLogonUserName = ""$SamAccountName"" and SMS_R_System.SystemOUName = ""$SCCM_SystemOUName""" | select Name
            $compCount += $computers.Count
            Set-Variable -Scope 1 -Name compCount -Value $compCount
            $computers
        }
    }
     
    Process {
        switch -regex ($(($SamAccountNames.GetType()).Name)) {
            "ADUser" {
                _checkSCCM $SamAccountNames.SamAccountName
                if ($PassThru.isPresent) {
                    if ($_ProgressTotal) {
                        Write-Progress -Activity "Getting Computers by User" -Status "Processing User: $(($SamAccountNames).SamAccountName)" -PercentComplete ((($userCount+$userUknCount)/$_ProgressTotal)*100)
                    } else {
                        Write-Progress -Activity "Getting Computers by User" -Status "Processing User: $(($SamAccountNames).SamAccountName)"
                    }
                }
                break
            }
            "String|Object\[\]" {
                foreach ($SamAccountName in $SamAccountNames) {
                    _checkSCCM $SamAccountName
                }
            }
            default { Throw("Unable to handle that Type: $(($SamAccountNames.GetType()).Name)") }
        }
    }
     
    End {
        Write-Debug "SamAccountNames Type:  $(($SamAccountNames.GetType()).Name)"
        Write-Debug "Total User Count:  $userCount"
        Write-Debug "Total Computer Count:  $compCount"
        Write-Debug "Unknown User Count:  $userUknCount"
    }
}