As the Microsoft Intern Ambassador and the CS Club Socials Chair, I've heard from multiple freshman and sophomores nervous about applying for an internship. Which is understandable. Venturing out into the 'real world' of software companies can be a bit intimidating. It seems like everyone around you has worked on multiple personal projects and knows more languages than you knew existed.
If this applies to you, TAKE HEART! I am here to tell you that you CAN get an internship as a freshman or sophomore and you WILL be successful during your time there over the summer. I've done it, and so can you.
Here are some common things you might be worried about:
1) Employers just don't want underclassmen.
False.
Two of the biggest computer science employers, Microsoft and Google, have programs specifically FOR underclassmen. Other companies will also be interested in you.
Why?
Because being an intern isn't /really/ about getting stuff done. It's not /really/ about you helping the company make a profit. While you will be getting a real project, it's not going to be a huge make or break moment for the company. What it's really about is recruiting. These companies want intelligent, driven employees, and one way to attract those people is giving them a great experience over the course of an internship. If a company can convince you that they are a great place to work at, then you are more likely to come back and be a great full time employee. So getting you early is hardly a bad thing for them.
2) I don't have enough experience to do well in interviews
This is something you can prepare for. Take advantage of this opportunity!
You DO know enough to do well, but preparing can help you feel confident and avoid silly mistakes. A lot of the interview is seeing how you think and approach problems. It's not just about what algorithms you know and what tricks you've picked up. So if you aren't on the right track, they will help you and it isn't a complete deal breaker like you might imagine.
You can also see real interview questions online. Keep in mind while looking at these that the questions are tailored to your level of experience. Sites like http://www.careercup.com/ can help you see what kinds of things you should expect to see. Taking the mystery out of it will help you feel more confident moving forward.
3) I don't know enough to do well during the actual internship
Not even remotely true!
You are not alone as an intern. You will have some variety of mentor or coach that will show you your project and the internal tools you'll be using. They are also there to help you if you get stuck and be a resource to help you learn.
When you are an intern, you are given a specific project. This isn't random: your team has chosen something that they think is reasonable for your level of experience and knowledge. As an underclassman this is likely to be easier than the project they'd give to a rising senior intern. So don't listen to people describing their internships and think 'Oh well if I don't understand that then...'
There's also so much you can learn about different languages and programming tasks just by searching around online. A lot of what you may be struggling with has been discussed online, and people will have posted their ideas and solutions. Your team will actually be impressed if you use these resources. You will never have to struggle alone.