Hi,
The MRF24WB0 has a companion chip called MCW1001 which has the TCP/IP stack built in and does the "heavy lifting". MikroE has their Wifi Plus module which is a module with these two parts. I've had one for a while but haven't got around to try it out yet. The Roving Network modules looks really nice too and most of them are cheaper than the Wifi Plus so I don't know....

/Henrik.