get-qaduser

Get-QADUser -sizelimit 100 | select lastname,firstname,logonname,lastlogon | sort {$_.lastlogon.value.ticks} |  convertto-html > test.htm

Dmitry's blog on using LastLogon:
http://dmitrysotnikov.wordpress.com/2008/07/18/finding-the-latest-logon-time/