Trespassing: I Have a Warrant in Another State for Trespassing

My question involves criminal law for the state of: California

I'm from Los Angeles, California. I was 19 at the time in Vegas with a friend visiting his family for about a week during June 2008.

My friend's cousin was a senior in high school at the time and he asked that we pick him up early from school. So we drove up to the high school and we got out and walked onto campus towards the main office to get him. Lunch had just ended so some of the security were yelling at us to go to class because they thought we were students there. One of the security insisted to countdown from 30 to 0 for us to get to class and suggested that we start running, we paid no attention to her because she was all the way across the hall.

She then ran over to us and stopped to question us on being late to class and that's when we told her that we didn't even attend this school and that we were picking up my friend's cousin. She was really pissed off because she told us there was a huge food fight in the cafeteria and I could tell she was just not in a good mood so she ended up writing me and my friend up for "trespassing" on campus because we didn't have any visitor's passes. Which is so stupid because we have to walk on campus to get to the office just to get a pass... anyways. Our court days were issued 2 months later sometime in August but we were from Los Angeles so we weren't going to go all the way back to Vegas just for a court date. It eventually turned into a warrant because we didn't show up and now I have this on my record and I want to know what I can do to clear this up?

Appreciate the time anyone has to give. Thanks :D