I do not do much AD work these days, let alone from PowerShell, but I do know of the AD cmdlets MS published. http://technet.microsoft.com/en-us/library/ee617195

Here is what I got (using replacement) with some basic PS in case you proceed down the current path. I could not find a slick split option or similar built into PS:

$str = 'CN=Admin-Lastame\, Paul,OU=Users,OU=Data_Admins,OU=Admins'

#$str

[string[]]$a = $str.Replace('\,', '~~~').Split(',')

#$a

#$a.Count

for ($i=0; $i -lt $a.Count; $i++)

{

$a[$i] = $a[$i].Replace('~~~',',')

}

$a