Fair warning - in my opinion, her biggest detriment is years of college experience. While it's quite true that you can be a great programmer and be a college freshman - big companies with established internship programs that offer the kind of things you are speaking of typically have a set of hardened criteria for reviewing applicants. One of them is years of college experience and most companies don't readily accept interns that are freshman - the earliest is usually after Sophomore year.
This is partially because interns - even if they are free - are an investment. They need computers, space to work, and the time of a senior person to supervise them. The cost of this has to be weighed against the value the intern will bring to the team. IMO - most interns are a good deal, but you can't take everyone so a company has to find some set of criteria.
So, knowing your cousin is a freshman tells me that if she wants a technical internship, she's already going to have to get creative - it's time to start using every under-the-wire resource and personal connection. You'll want to maximize your contact with people who will see working with her as a plus - and that's a heck of a lot easier with people who know your cousin.
The other venue that is ALWAYS worth maximizing is her college's internship system. Most colleges have internal internship job boards where the college and the internship providers have worked together to build a set of opportunities for students. In these cases, the companies realize that they need to give interns a good opportunity.
I'm assuming that at this point, though, your cousin has tried everything and she's really scrounging - going to just about every job board and trying just about every opportunity. Assuming she gets an interview, she'll want to remember that interviewing is as much about checking out the company as it is about showing potential. Here's some things I'd look for when going on an internship interview (now that I'm well past my intern years and I know from the other side exactly what a manager can do with an intern!). I'm keeping it broad as IT is a heck of a lot more than just software work!
What will I be working on? - good signs are work that involve either making things work or verifying that they are working. Bad signs are doing paperwork while other people make things work. Having to service customer problems (front line tech support) isn't all bad, it may all she can snag, but if that's the case, she should be getting paid.
Who will I be working for? - preferably it's someone on the interview list or someone on the interview list is "sample manager" - ie a manager who needs interns, but the company may assign the candidate to a similar but different manager in the end - it's just that managers have to handle pools of interviews and often matchmaking is done later on. Ask this manager what they expect from an intern and what they are willing to give. Good signs are "I expect you to take responsibility", "I expect you to ask lots of questions", "I expect you'll keep me appraised of your status", "I expect that by the end of the internship you'll be able to take on a 3-4 week chunk of work and work with minimal assistance". Bad signs are - "you'll follow me around and do exactly what I tell you", or "I won't have time to give much guidance, and I don't have anyone that can help, we'll have to figure it out as we go".
How big is the technical team? - hopefully it's a team of 5-10 people with varying degrees of expertise, with at least a few senior people. Also - how much time will the senior people have to spare to answer questions? Good = 15 minutes a day, with a known rampup of longer than that early on. Bad = "what senior people?" or "it's just you".
What are the major goals of the team? What are the key ingredients to success on this project? - this is my particular way (when I do volunteer work) of figuring out whether I've found people I can work with. If it takes 20 minutes to answer this question, we have a failure. Even if I am working alone, with a non-technical person, I may learn a lot of good stuff. But that requires that the people I'm working with have a real clue of what they want to get done. It's amazing how many people really don't know what the problem they are trying to solve is, or what qualifies as a solution. Without that core vision, no matter how technical the team is, it's likely that the internship will be frustrating.
All that said - seriously - don't feel awful if an internship doesn't happen in the summer of Freshman year. I had pretty great grades, 3 languages under my belt and a programmer mother and I STILL didn't swing an internship my Freshman summer. I used my touch typing skills to qualify as a Temp and worked answering phones, typing and filing microfiche (boy am I old!) my Freshman summer... at least I got to hang out in A.C.!