On my E71 using the inbuilt SIP features I have various incoming DID's that ring the handset directly whilst I am in 3G, 3.5G or WIFI coverage areas. When I am in 2G they automatically divert and look for me on GSM (at forwarded charge of around 5c/min) Dead straightforward to setup though maybe it takes a bit of a geek. I can't see why someone couldn't sell a package like that, though you might as well set it up yourself. DID's that ring both a SIP address and a PSTN number simultaneously have been around for ages. I used one with Gradwell in the UK at least 3 years ago. Personally, I can't see much use for them in the specific case I outlined above. There would be no point in simultaneously ringing the SIP and PSTN if both are on the same handset.