All athletes who are planning to compete at the major USA Wrestling events scheduled for Las Vegas, Nev. next week must pre-register for the event right away.    The events that have MANDATORY pre-registration are the 2005 United States National Wrestling Championships, the Men's FILA Junior National Championships and the Western Junior Regional Championships. These events will be held at the Las Vegas Convention Center in Las Vegas, Nev., April 27-30.    All athletes in all divisions MUST pre-register online or by mail before Tuesday, April 26 at 12:00 noon Pacific time.     THERE WILL BE NO ON-SITE REGISTRATION OR LATE REGISTRATION. THERE ARE NO EXCEPTIONS TO THESE PROCEDURES.    To pre-register, visit the following website:  http://www.lvsports.org/events/wrestling.entry_form.main.html    If you plan to participate and have not pre-registered, you must do so by noon Tuesday  (TODAY).    CLICK the links below to see the pre-registration entry list for all three tournaments in Las Vegas. This is as of Monday night. If you are not on the list, you are NOT in the tournament. You must go on-line and register this morning to be entered in the competition.    U.S. SENIOR NATIONALS ENTRY LIST (as of Monday)  http://themat.com/pressbox/pressdetail.asp?aid=12243    FILA JUNIOR NATIONALS ENTRY LIST (as of Monday)  http://themat.com/pressbox/pressdetail.asp?aid=12244    WESTERN JUNIOR REGIONALS ENTRY LIST (as of Monday)  http://themat.com/pressbox/pressdetail.asp?aid=12245    If you believe you have registered and do not find your name on the list, contact Tournament Director Larry Barnson of the Las Vegas Sports Committee at 702-499-3231.