Three students from 2009 were kind enough to allow us to post their applications as examples of the sort of thing that gets you in: [[SummerOfCode/SampleApplications/1|1]], [[SummerOfCode/SampleApplications/2|2]], [[SummerOfCode/SampleApplications/3|3]].
And when you come to put your experience on your resume, [[FreeSoftwareOnResumes:Writing|this page]] might come in handy.