Adding the ability to forward phone calls to the N900 would be one of the best additions to functionality to date.

Ideally it should go in the phone menus alonside the "hold call" function, but I suspect that's code that is only in Nokia's hands. If we can't get it there, the next best place would be on the power button menu. I think there are some packages that add to this menu, but I can't remember which ones they are. This program should pop up a contact selection dialog, perhaps laid out as a scrolling grid like this:

where each available numbers is a separate button. (Skype contacts, etc., have been left off purposely as they are using a different transport and probably different mechanisms.)

Tapping one should lead to a full screen confirmation dialog to avoid significant social embarassment. This would then HOLD the first call, call the new number (probably via a DBUS commands to the phone application) so you can make an introduction, and change the action so that the next time the power button menu was chosen it would issue the command Fredrik75 has discovered.

Or should that all the GUI logic be dispensed with? Have the phone user make a second call, just like normal, to introduce the original caller-and then press the option added to the power button menu that would issue the command? The problem then becomes what to call the action, because it is not properly called "forwarding", as the action has already been started..."Leave conference"?

The second approach is much less work and gives the same functionality, but it's not the way that people will expect to forward a call.

Which is the best way to go, given that we really hope Nokia adds forwarding the the N900 properly in the Phone application?