I need music for a bslideshow im making?

my brother is havuing a graduation party tommorow and im making a slideshoww and i wantedd to play it at the end of the party so i put pictures since he was a baby till now but i need music i want to putt forever young,mama im coming home,son of man, we ae the champions and schools out the video is 10 minutes long so i was going to trimm the songs to get the right time but where can i get them by the way im using windows live movie maker i wanted to download them from youtube but idont know how and this is really stressing me out please helpp!:)