If you use iphone, there is a copy of skype wifi that you can download from apps store. It allows finding and autologin but bears in mind those hotspot will be a bit more expensive
There are two directions:
1. Asterisk => Handhold unit(Skype/Gtalk/Obitalk)
2. Handhold unit => Asterisk
Currently, Obitalk is the best choice. Skype <=> Asterisk(especially skype to asterisk) is hard to fix without Linux box.
Yes, complicated and more complex tasks need an linux server to handle.
IP01 has positioned a simple and easy to use asterisk based ippbx. Especially after switchfin firmware, the functionality improved but we have not attempted to put in a lot of things.