ON-LOGON Trigger ??

Hallo,

I would likre to write in PL/SQL small tool for dba-s,that will note from "V$SESSION" for any, login username and other datas into a table, something like "last" on UNIX, but I don't know how to write and compile this function with that trigger(ON-LOGIN, if this exysts), so I need a little help.

                                 Thanks in advance, Robert !
                                 robert.bralic_at_si.t-com.hr