I guess handset manufacturers didn't have a real urge to build WiFi into their phones as most mobile phone networks saw it more as a threat than a chance. Now Nokia has released the first Wifi enabled phone. Technology Review sums up the trend of the conversion of classic GSM and WiFi phones. I'm sure we will see more of these articles soon...

Also I'm still wondering why Skype isn't available on PDAs or Java phones? It would solve many issues (especially my still enormous international call bills) and you could easily use any hotspot as a zero cost phone booth...