Can bitcoins be exchanged for cash
Yes! A variety of ways to exchange bitcoins for cash are available.
The simplest method, if you are lucky enough to live in a supported country, is to use Circle. They allow buying and selling Bitcoins with just a credit card, and your account is available to use without having to wait for bank account verification. As an additional bonus you won’t find anywhere else (as far as I am aware), Circle account balances, in both national currencies and bitcoins, are fully insured.
Another excellent option for those who have a bank account and live in one of 19 countries supported, is likely to use Coinbase. A transfer of Bitcoin and a few clicks will have your choice of national currency deposited into your bank account within a few days.
Bitcoin exchanges such as bitstamp and btc-e typically allow deposits and withdrawals from bank accounts as well, though usually not as conveniently and user-friendly as Coinbase. The advantage of selling on an exchange is that you may set your own price and wait until buyers are willing to pay that price before selling. Coinbase and Circle both sell immediately at market price.
Another option, though perhaps less safe, is to use localbitcoins.com to find a private buyer locally or online. Note that those using localbitcoins typically use it to avoid taxes and compliance with local regulations and laws. And though thefts are rare, they have happened, even in person. Meet in a public place and agree on a process for the transaction before meeting.
As always, do your own research to ensure the entity you are dealing with is reputable and complies with whatever level of risk you are comfortable with.