Cracking WPA? Is it possible?

Wireless networks are commonly used by people. Market devices are equipped with the new security standard 802.11i. The standard announced in the middle of 2004 is commonly used to protect WLANs. Currently we can find the information that vulnerabilities were found in that standard. Then a question arises: Are WLANs compromised again? The article describes vulnerabilities which were discovered in the new WLAN security standard. It explains how the four-way handshake process works. Which part of that process can be used to break through our network? What kind of devices should we possess to check that vulnerability? What kind of protection can be applied to avoid such vulnerability?