Right now you can get comunicate with skype and your nokia n770 or n800
my solution is tapiocca, gtalk2voip ipkall forwarded to gtalk2voip then skype forwarded to ipkall. to start a call to skype use sms4skype.net.(+41762203200) the pretty well covers it all
in the n800 google talk might work better than tapiocca. it will cost you 5 bucks for gtalk2voip and you'll have to get skype out to pay for forwarding to your ipkall number, but the ipkall number is free all and all its is ok but your friends have to know it will take a while to connect