The nRF24l01+ transceiver is a fantastic and cheap way to get your Arduinos talking to each other wirelessly. It’s also very easy to use thanks to some great libraries:
Each library has some great examples and is fairly well documented, especially the RF24 libraries.
Feel free to download the libraries and use the included examples – they are fairly well documented. Also be sure to check out Maniacbug’s website which has some great posts on the nRF24l01+ modules.
Also, here’s a pinout that will prove to be very helpful: