Volunteering offers students a number of benefits:
You may go into a volunteer opportunity as a blank slate, there to learn everything you can, or you can seek out an opportunity where you'll serve as the in-house expert.
For example, many organizations are looking for more ways to get involved in social networking; if you're a "digital native," fluent in Facebook and Twitter, you could help an organization get started by building social media presence, while learning how to apply your knowledge of social networks to an organization's needs.
The key here is to find a volunteer opportunity that helps you achieve your goals.
Here are a few websites on student volunteering that you might want to check out: