Below is a collection of resources related to breaking into product management out of College.
Content about Product Management, PM Interviews, and APM programs
Martin Eriksson answers "What, exactly, is a product manager?"
Asana's Product Lead - "College Students, Product Manager is the best job you've never heard of"
ProductSchool has various courses and lessons on breaking into product management, as well as a large community of aspiring PMs. You might start with this post specifically about the Google APM program
PMLesson has in depth online courses on PM interviews
ThePMInterview.com lists a number of sample PM interview questions
PMInsider is a medium blog which regularly has guest writers from the tech product world write about product management
There is a ton of content about associate product manager programs on Quora. Start with my answer here on how to get into programs like Google APM, and then explore related questions on the right.
Publications and Newsletters on the Tech Industry
Subscribe to these to keep up to date on tech trends, which can help a lot in PM interviews.
Stratechery has some great analysis on the tech industry. The subscription is 100% worth it.
CB insights gives an excellent daily summary of tech trends and investments. This is the funniest, most enjoyable newsletter I regularly read.
Fortune has a number of daily newsletters which cover everything from VC/PE investments to the tech industry at large to a "CEO Daily" newsletter. A great way to stay up to date on every corner of the business world.
Pitchbook's newsletter has analysis of recent deals in the tech industry, as well as links to interesting articles about business and tech.
Strictly VC gives a nice daily summary of happenings in the VC world.
Mattermark has a daily newsletter that covers some of the most interesting blog posts from leaders in the startup and tech world.