WiFi SDIO cards for PDAs are what some brave souls have used. Very, very difficult though. That chip referenced above is likely so encumbered. Much of the MAC is not in that chip, nor IP and all the rest. Some try to adapt Linux drivers (megabytes of source code).
Easy: Buy a LANTRONIX WiPort or lower cost Matchport module. Connect its 3.3V serial port to the serial port on your microprocessor. Configure the WiPort to be either a transparent serial cable replacement, where a virtual COM port on a PC connects to the serial port on your microprocessor (freeware with WiPort), or use WiPort in the UDP or TCP connection mode, where your own special software runs on a PC.
There are two versions of the WiPort: one can be custom programmed, and another lower cost one cannot. Both have a web browser interface to
configure the many settings.
http://www.lantronix.com/device-network ... hport.html
http://www.lantronix.com/device-network ... iport.html
I have used WiPort. It'll take you an hour or two to get it working with this serial port scheme.
THere used to be 2 or so other competitors.
I wish Sparkfun would carry these. Digikey and Mouser sell these, but there are minimums, with these big guys.