Hey there just seen this sorry for the tardy response.
I would avoid Palm if I were you - I have a TX and I love it to bits - for everyday life it's my best friend, email, web, calendar, contacts etc... but then I took it on the road with me and discovered 2 things
1 - Wi-Fi doesn't necessarily work with the browser
2 - The browser is really rather crap.
In essence what that means is that if you sit down in an internet cafe and connect to the wi-fi (that's the easy bit) then fire up the browser - the browser should accept a re-direct from the router to take you to the relevant payment / registration page.. however... the palm browser wont accept that re-direct and you have to try asking what the address of the page is, and in most cases the poor guys working at the cafe have no idea what that is.
I have no idea about the Windows based PDAs sorry!
For my money I'm going to get one of these...
For £150 is cheaper than most PDAs and it's only very very slightly larger / heavier - plus it has a fully featured browser (firefox), skype, and email clients... not to mention a proper keyboard and OpenOffice.
Hope that helps.