You can use one of three programming languages when using Unity, C#, UnityScript, a variation of JavaScript, and Boo. Each of these programming languages has its pros and cons and it's up to you to decide which one you prefer. My personal preference goes to the C# programming language and that's the language I'll be using in this tutorial.
If you decide to use another programming language, then make sure to take a look at Unity's Script Reference for examples.