While there are no known cryptographic attacks against AES,TKIP (which can be used with both WPA and WPA2) has been shown to be vulnerable to some classes of attack. By FAR the primary attack vector for both WPA and WPA2 is the pre-shared key. Attacking a WPA or WPA2 secured network with a weak pre-shared key (aka password) is a very simple matter with commonly available tools (which have a wikipedia page, so they can't be that bad ;) Use them only for good to test your own network...)
The tools that are publicly available can remotely de-authenticate an authorized user and then capture the authentication traffic (only 4 packets are required if I recall correctly), at which point the pre-shared key (aka password) can be brute-forced offline (again with commonly available tools, and massive rainbow tables are available to significantly speed up the process). Just as with most cryptographic systems, the password is the weak point. If you have super-fancy high-end Cisco wireless gear secured by WPA2 and use a password of mypass, you are ripe for compromise.
If you are looking to invest in something to secure your wireless network, choose AES over TKIP, and use a long password (pre-shared key) with high entropy (Upper, Lower, Number, Special Characters, etc). If you want to go buck-wild, setting up 802.1x/RADIUS will do much more than moving from WPA to WPA2 (although that would require a significant amount of time/knowledge to setup and administer).