From the gumstix (running Angstrom, and bluez 4), I can do hcitool scan and see my laptop.
I can use hcitool cc <bdaddr> or hidd --connect <bdaddr> and the gumstix will then show up in "my bluetooth places"
However, when I go to connect to the serial port, under the gumstix bluetooth place, it prompts me for a security pin (the next button is greyed out until you enter something for a pin)
I've tried a bunch of pins, 1234, 123, 1111, 2222, 0000, 111, 222, 000, but nothing has worked.
According to the angstrom manual, written in Feb 2010 (http://www.linuxtogo.org/gowiki/AngstromManual), you set the pin by entering it into a file called /etc/bluetooth/pin.
I've done that, but still no luck...