Okay, so you know how when you listen to music on your iPod or computer, you don't see the songs on a big round CD that spins around? Instead, you just click on a little picture of the song and it plays. Vinyl emulation software is kind of like a pretend version of the big round spinning CD.
It helps people who like to DJ (that means they play music for a bunch of people at a party or club) make their music sound like it's being played on a real record player. The software makes the music sound scratchy and have a hissing sound like you'd hear on a real record.
Sometimes DJs like to use this software because it lets them do cool things with the music that they couldn't do on a regular record player. They can add special effects and change the pitch or speed of the music to make it sound different.
Overall, vinyl emulation software is just a fun way to make music sound like it's being played on a record player even if it's really just coming out of your computer speakers.