Hey there:
I just graduated from USC and was part of their distance program for my first two years. You can definitely run there. While they don't have ncaa xc for men, the track team has an integrated club xc team that trains even the 800 guys. Coach Alice personally coaches the male 800 guys along with Lazlo Tabori, an old throwback who was the 3rd miler under 4 back in 1957. While some of his methods seemed a little archaic to me, he definitely trains guys well for speed. He will have you do lots of quality intervals.
Between school and work, I ran out of time and energy keep up competitive running by my junior year, but I am quite glad that I was able to be part of the program. As a walk on distance runner, you'll be treated as somewhat of a second class citizen compared to the rest of the team. However, perks like registering for classes first, having access to awesome training table meals at the galen center (not the b-ball stadium) and top of the line training personnel more than make up for this.
Regardless of whether you end up coming out for track, you're in for a college experience like none other. There's an atmosphere of enthusiastic ambition there that's unlike anything I've ever come across. Also, the combination of being in downtown LA and having the largest international student population of any US university, the USC campus is one of the most the most diverse places in the world. And between you and me, we're going to annihilate everyone in the country this year on the turf. My email is linked to my user name. Feel free to contact me with any questions you may have regarding the track program or anything else.
Fight On!
-Peter