Free Radio Network (FRN) is FREE software that you can use to turn your computer into a CB radio!
After downloading the software (link below), you just need a microphone and speakers or headphones (even the built in mic/speakers in your laptop will work) and you are all set, you can now communicate with other FRN users all over the world. You do not need a huge antenna outside, and, as its basically connecting through the internet, you do not need any kind of CB or Ham Radio license.
FRN is a great way for old 'breakers' to get back 'on the air' or new users to try out the world of radio communications without spending loads of money on expensive gear. The software is free, and if you find you don't enjoy it, its easily un-installed.
And as a bonus, you might just hear me on there! My handle (or radio nickname/callsign) is 'Warf', so join FRN and give me a call!