What's the difference between WPA and 802.11i?

What's the difference between WPA and 802.11i? Are there any 802.11i products yet? Wi-Fi Protected Access (WPA)...

is a Wi-Fi Alliance snapshot of the 802.11i standard, frozen back in October 2002. It uses RC4 for encryption, with key mixing to avoid cracking risks associated with Wired Equivalent Privacy (WEP).

WPA2 is the Wi-Fi Alliance's brand for the final 802.11i standard, ratified in June 2004. WPA2 is a superset of WPA, adding several new features:

1. AES encryption becomes an alternative to RC4 encryption. AES is more efficient and ultimately more secure than RC4 when used over 802.11 wireless.
2. 802.1X Authentication can be used by ad hoc (peer to peer) 802.11 connections. 802.1X can be used with WPA for infrastructure (AP-based) networks only.
3. Options for speeding 802.1X re-authentication have been added, including key caching and pre-authentication. These are particularly helpful for VoWLAN.