I've Slackware 14.0 on my PC. It's connected to internet througth a ppp0 interface (dial-up mobile "3g" usb-key). I've also a bluetooth usb-dongle which was/is used to transfer files between cellular phones and PC.

Now I've also an android smartphone with bluetooth supported.

I'd like to share the PC internet connection with this phone.
I mean a network phone-PC and access to internet with the phone through the PC internet connection.

In this configuration my PC will be the "access point" that provides internet connection and my phone the "client".

I hope, I've been clear (my bad english doesn't help... sorry).
To be more clear:

Search for a solution I've read that I need to cnfigure bluetooth to work as NAP (network access point).

My smartphone is paired and trusted on the PC bluetooth. I can connect it for file transfert etc...

Now NAP config would seem quite easy to set up using blueman-applet in KDE:
Right click on blueman-applet
-Local services
-Network
-select network access point (NAP)

But when i click "Apply". It returned an error poup-up:
Uhmmm... I don't know if it's a bug or if I had to do something more before...

I've also searched for a more raw solution, with some manual config, but I didn't found a clear solution.

So I've decided to ask there.
Hope somebody could help.
Thanks in advance!

How much time are you willing to invest in this project?
All you have to do is configure SAMBA as a domain controllers and have the phone logon to the domain. That will work.
The question I have to ask, though, is are you willing to invest the time to learn how to do that?
The first step is reading the SAMBA manual, let us know it you have any questions.

I solved in part with bluez "test-tools".
Slackware doesn't include them, but you can get them from the source tarball of bluez-4.99, under subdir "test".

I've used simple-agent and test-device to for phone pairing and trusting on slackware system.
Then I've launched "test-nap".

Then on the phone I can select the bluetooth option "use this for internet access".
Before test-nap launched, there was that option but I can't select it.

At this point on the system appears a new interface called "bnep0".
We have to assign to it an address IP.
Then we have to let the system give the phone an IP too, I chose dnsmaq for that.

Finally we have to add a rule to nat table for address masquerading on POSTROUTING chain throught our internet interface (ppp0 in my case).
If we usually have other restrictive rules in iptables, we have to add also some others rules to let INPUT packet from bnep0 interface and unlock FORWARD packed between bnep0 and "ppp0" (or wathever is your internet-side interface, eth0 eth1 and so on...).

The big matter is that "test-nap" is not a server, but just a testing tool.
Now I'd would like to understand how to configure "bluetoothd" through its "/etc/bluetooth/*" files.
It seems theese infos are hidden somewhere in bluez developers minds. Also "man bluetoothd" refers to a misterious "man /etc/bluetooth/main.conf"... but I've not found it yet!

PS.
Isn't SAMBA for mixed win/unix networks...???
What does it deal with bluetooh PAN? I didn't understand your suggestion...

Thanks anyway.
See you