[mibok]

when buying my ibook i didn't realize that i could add internal bluetooth, so i didn't do that... now i need bluetooth and i don't want to carry a dongle all the time. so i was thinking that since there is an internal usb port on the mainboard there has to be a way to add (maybe solder) an usb bluetooth adapter on it.

has anyone ever tried this?

[Cadaver]

This has been discussed over on the PowerMac forum, too (adding internal BT after-the-fact).
Looks like you'll have to find somewhere that can order you the internal module as a service part, and you'll likely have to disassemble your iBook to get it in.