My Imac is new and doesn't have bluetooth

Okay, let's see: your signature says you are on 10.6, but you said you're on 10.5.8? Can you please check and report back.

And, please go to the Apple, click on about this Mac, then click on more info, and you should wind up with a window like this:

Please post back what is says under Model Identifier.

And, you see the Bluetooth under the Audio? Can you see that on yours?

I would suggest that you open System Information by clicking on the little apple in the upper left hand corner of you screen.

Then under Hardware, click on Bluetooth.

Report back what you see.

On my Mac I see the following;

Apple Bluetooth Software Version: 4.0.1f4

Hardware Settings:

Address: 78-ca-39-c0-d9-a1

Manufacturer: Broadcom

Name: Allan Eckert’s Mac Pro

Firmware Version: v191 c425

Bluetooth Power: On

Discoverable: Yes

Vendor ID: 0x5ac

Product ID: 0x8215

HCI Version: 4 (0x4)

HCI Revision: 425 (0x1a9)

LMP Version: 4 (0x4)

LMP Subversion: 8639 (0x21bf)

Device Type (Major): Computer

Device Type (Complete): Mac Desktop

Composite Class Of Device: 3801348 (0x3a0104)

Device Class (Major): 1 (0x1)

Device Class (Minor): 1 (0x1)

Service Class: 464 (0x1d0)

Services:

Bluetooth File Transfer:

Folder other devices can browse: ~/Public

Requires Authentication: Yes

State: Enabled

Bluetooth File Exchange:

Folder for accepted items: ~/Documents

Requires Authentication: No

When other items are accepted: Ask

When PIM items are accepted: Ask

When receiving items: Prompt for each file

State: Enabled

Devices (Paired, Favorites, etc):

Apple Magic Mouse:

Address: c4-2c-03-b2-66-fb

Type: Mouse

Firmware Version: 0x87

Services: Apple Magic Mouse

Paired: Yes

Favorite: No

Connected: Yes

Manufacturer: Apple (0x3, 0x31c)

Vendor ID: 0x5ac

Product ID: 0x30d

EDR Supported: No

eSCO Supported: No

Incoming Serial Ports:

Bluetooth-PDA-Sync:

RFCOMM Channel: 3

Requires Authentication: No

Outgoing Serial Ports:

Bluetooth-Modem:

Address:

RFCOMM Channel: 0

Requires Authentication: No

It seems that yours is an educational model? Here are the specs:

http://www.everymac.com/systems/apple/imac/stats/imac-core-2-duo-2.0-20-inch-alu minum-early-2009-education-specs.html

See the first couple of paragraphs: there is no built in Bluetooth and the model has a few other things that were different from a regular iMac. I do not believe it could be added now; however, there are bluetooth dongles if you can find one that'll be compatible with the Mac.

Your iMac9,1 is from Mid 2009, and Bluetooth is not included.

I have never needed to add Bluetooth to a Mac. But here's an Apple support document in which an accessory is recommended:

http://support.apple.com/kb/HT3043

You can also Google:

USB Bluetooth dongle Mac

for more information.