i tested fring, twitter and nimbuzz on my Samsung Omnia with windows mobile.
On windows mobile you have internet access e.g. for 1 MB = 1 Euro. So get a phone and add this option to be mobile on the internet.
But we need retroshare as well on windows mobile and android for linux.
If you test your IP adress with www.whatismyip.com
you get a real IP on the mobile, so retroshare mobile should work?
Is there any development for this?