I have two USB bluetooth dongles: Dlink DBT-120 and a non-brand one with ISCC chipset. I thought it was easy to install by just plugging them into the computer and installing the drivers. However, it is not that easy. First of all, Dlink DBT-120 needs a security license to install its own driver. Since it is a second-hand unit, I cannot find the code. There are two choices of bluetooth software, one is from widcomm and another is called BlueSoleil. Both of them need license. I finally managed to find patched drivers on the Internet and get both installed. DBT-120 is working fine but the other cannot find any bluetooth devices (although the driver seems starting properly, I suspect it might be a fake product). I guess my DBT-120 (dev A2) doesn’t have Audio service, so it needs a firmware upgrade. Originally I bought it for my Mac, but later realized that only dev B2 (or later) can work fine with Mac OS X.

Here are some tips for installing DBT-120:
1. Use patched Bluesoleil_3.2, it works very well. However, be careful with the driver (use the driver Bluesoleil provides). Here is the VID: 0A5C, but PID varies: 200A (current one) or 2033.
2. Following Jon’s guide, it should work in most cases. This time, a generic Broadcom bluetooth driver will be installed.
3. If the driver is messed up, try to use Dlink official driver to recover. Then uninstall the software, but the driver remains.
4. No time to upgrade firmware, guess it can add Audio service into DBT-120 dev A2 (I guess it uses CSR chipset, so a generic CSR firmware may be helpful, check this out).

ISCC one has VID 1131 and PID 1001.

A useful forum: http://forum.gsmhosting.com/vbb/forumdisplay.php?f=237
A useful guide: http://bbs.btbbt.com/thread-3059793-1-1.html teaching how to let bluetooth software recognize new type of USB dongles.