I have one "built in" to my HP Pavilion laptop (ZD8000). I have had success using a 2.6.12 kernel using the latest bluez source packages (as of 20050811). I have been able to connect and use a Logitech MX900 mouse and a cheap no-brand bluetooth mini-mouse. I was also able to pair my SonyEricsson z800i, but haven't got round to any data transferal yet.
Haven't done any range testing yet, tho, being an internally mounted module, I'm not sure what kind of antenna it has attached. While scanning at home it did pick up a nokia, probably belonging to someone else in my appartment block, but couldn't say how far away they were.
The only problem I have is that the BD address is always reported as 00:00:00:00:00:00, even if the device is up and running. I'm beginning to delve a little now, but have also been considering checking out Nokia's Affix bluetooth stack and tools. Also, I have to specify the device every time - the hci utils don't seem to default to the first available device like their documentation says. This could be related to the BD Address issue though