When I first starting reading up on the E series I thought I saw some mention of the ability to use the E60 within the company PBX with support for 4 digit (extension) dialling.
It seemed to disappear from the blurb on the Nokia site but as Mobile Burn have confirmed it is there.
This is good news as now it opens up a realm of possibilities. If you are using a PBX with wireless support; something like Asterisk, then you can configure the SIP settings so that when you are within range of the WAP your shiny new E60 can be used as your normal deskphone.
Impressive but so what? Asterisk 2.0 also supports Gizmo a SIP Softphone VoIP client similar to Vonage and Skype.
This now allows me to route calls from Gizmo to me mobile handset. That's pretty useful if you're on Gizmo which is very US centric but does support Call In in the UK and Spain. It comes with the usual Call Out and Gizmo->Gizmo free calls.
All very nice and relatively easy to do. Asterisk runs on Linux and so the whole platform supports the growing trend in OpenSource adoption in the SME market.
The final step in the chain is something that many people have talked about already. Using your WiFi router to host some of this stuff. I use Belkin at home and I'm very happy with it, I piggy back onto the ADSL modem so I can have an always on connection wherever I am in the house. Belkin is a supported provider in the openWRT forum
OpenWrt is a Linux distribution for wireless routers. Instead of trying to cram every possible feature into one firmware, OpenWrt provides only a minimal firmware with support for add-on packages. For users this means the ability to custom tune features, removing unwanted packages to make room for other packages and for developers this means being able to focus on packages without having to test and release an entire firmware.
So I can now change my firmware and run the a Linux distro on my router to host Asterisk*
The total solution is ideal for SME's as I get a very cost effective PBX for my business that can scale nicely if I build out the connectivity by adding some access points as well.