The Advanced Encryption Standard (AES) is a block cipher used as an encryption standard. It is a very reliable method of encryption, even approved by the U.S. National Security Agency, marking the first time that a cipher approved by the NSA is also available to the public. AES is spreading all around the tech world and beyond. It is used to encryption data and transmissions in all different environments and doesn't seem to have any known fundamental weakness. It was developed by Joan Daemen and Vincent Rijmen, who originally named it Rijndael.
AES is now used in securing wireless network data transmission with WPA2. Both its predecessors in the field, Wired Equivalent Privacy (WEP) and Temporal Key Integrity Protocol (TKIP) have been found to have weaknesses. To be fair however, the flaws experienced by WEP are so huge that a WEP-protected network could be compromised in minutes with software that is readily available and very easy to find, whereas the vulnerabilities within TKIP do not allow for such a level of compromise.
Regardless, using WPA2 with AES encryption for now is the recommendation among security experts.
More Information: Wired Equivalent Privacy (WEP), Temporal Key Integrity Protocol (TKIP), Wi-Fi Protected Access (WPA), WPA2