Hi Christian,
Use the report RSUSR200.
You can get information regarding the "user valid/non-valid today" and also "Password Changed with Date -->The user changed his or her password on the specified date". So if your policy is 60 days, then you can also see which user need to change their password already or soon.
See the explanation on this help-doc: http://help.sap.com/saphelp_nw70ehp1/helpdata/en/1e/478f40f3b19920e10000000a1550b0/content.htm
I hope this will help you.
Regards,
Andre