Same company? You can probably list them once and provide the month/yr to month/yr that you worked.
If you switched companies it's a separate listing.
Joe's BBQ Shack - 5/03-8/03, 5/04-8/04, 5/05-8/05.
or
Joe's BBQ Shack - 5/03-8/03
Prison guard - 5/04-8/04
Prison inmate - 5/05-8/05.
Saying 'college break jobs' 2003-2005 isn't enough.
The details matter(prison inmate ^^). ;-) Don't have a start and ending date, August 2002-May 2005 when you only worked three months of each year. There's a difference between working as a full time student vs working on your summer breaks. If you have to start clarifying answers, especially repeatedly because your resume is presenting a story that doesn't match the facts, the human dynamics of the interview can change against you.
The common response is 'all jobs after H.S.' or 'all jobs after college'.
If you're writing resumes prepare two using each of the usual formats. ^^
Single line format for small jobs is fine -
May 2003 - August 2003. Acme Lawn Care, Manhattan, NY.