Student loans come in two basic types: those provided or sponsored by the federal government and those that are not. Federal loans usually offer better rates and terms than private education loans, which is why you should opt for those first.
(By the way, just because a loan is sponsored by the federal government doesn't mean Uncle Sam will be your actual lender. Private lenders like Citibank offer federal loans as well as private loans.)
Federal loans may be subsidized or unsubsidized. If they're subsidized, the government pays the interest while you're in school. Otherwise, the interest starts accruing from the day you get the loan, even though payments probably won't be due until you graduate.
Once again, you'll ...