The sooner you start looking, the easier it will be. Alot of students at semester schools figure out internships in March-April, so if you are in or near one of those, you may find that alot of positions are already filled. I'd imagine most people on the quarter system are already looking or have set something up by now too.
Every chain is different, and interviewers have different preferences. One of my classmates with no tech experience was placed at the CVS by my house. I also applied for the position and I had alot of experience. When my interviewer asked me some initial background questions and found out that I am from the Seattle area, her next comment was that she found that people not from the Midwest did not seem to be easy to talk to in her experience and she didn't think she had any interns that weren't from the Midwest. You wouldn't think of that as a hangup a recruiter would normally have, but, whatever.