ok first off you should have read other posts i have seen this question many times
go to your mta.exe and start it click play mta(sp is single player) once you start a new game(when the credits are going) alt+tab and you will then want to start up ase, pick a server, click into the server window which auto launches when you start mta and copy ip WALLAH!!!! click back into gta3 and after a few seconds the credits should disappear and your in....