dig it
i use VOIP on my 5500 and it works great. i wrote this some time ago on my stumbleupon blog. here ya go:
Great VOIP hook up!
Packet8 packet8.net [packet8.net] ) is a provider of broadband phone service for business and residential users. It works great with my Zaurus SL-5500 linuxdevices.com/articles/AT2134869242.html [linuxdevices.com] ), Free World Dialup pulver.com/fwd/ [pulver.com] ), and KP/Pi pi-sync.net/html/kp_pi.html [pi-sync.net] ). Basicly, anywhere there is free wifi(like everywhere) I can use my Zaurus with the KP/Pi program to dial out with my FWD account. I can call my Packet8 number which in turn can be forwarded to any number of my choosing via a web interface.
Voila! Unlimited calling to anywhere in the US and Canadia fo' free right from my Zaurus.
YeeHaw!