Good morning

Many cameras have digital media cards which are more compatible through USB readers than directly connected to the computer. The advantage of using a reader, is that you don't waste valuable camera battery life. It would help to know what camera you have.

Yes a SIM card reader that supports the same standard as your camera. Leopard was the last operating system Apple had that supported PowerPC applications on PowerPC Macs. Snow Leopard may work better if you install Rosetta. Rosetta is gone with Lion, and you need to make sure that whatever application you have is coded for Universal code for the Mac. Easier would just be to get a driverless SIM card reader. Sans Disk makes quite a few models. Check with them which works best with 10.5, 10.6, and 10.7 that supports your SIM card. 2006 was right when Apple started moving to Intel Macs, so the pre bundled software that came with your camera probably is not ready yet for full Universal support, but an update may be available from Nikon.

http://forums.printable.com/showthread.php?t=1110

Explains how to manually install Rosetta. Normally when you do a simple upgrade Rosetta should install automatically. Though for whatever reason, it sounds like that didn't happen for you.

Rosetta is on the SL install disc as an optional installation.

To check what versions of software you have, open the System Profiler;

 > About This Mac > More Info

and go to the software section (down the left side) and select Applications. That will bring up a list of all applications on your Mac (takes a little while to load, so don't panic if nothing seems to be happening for a minute).

One of the columns gives you the application type - Intel, Universal, PowerPC, (and just possibly Classic if you've migrated from 10.4)

Intel - will run only on Intel processors

Universal - will run on Intel or PPC processors

PowerPC - will run only on PPC processers or under emulation in Rosetta

Classic - won't run at all.

Luca, They patched the security update with version 1.1 Make sure you are installing that version and not version 1.0, which did anul Rosetta.

https://discussions.apple.com/docs/DOC-2921

There is an additional security update for 10.6 now that the Flashback trojan was discovered:

http://support.apple.com/kb/DL1516

You appear to have posted simultaneously with a.brody;

Read his post and try applying the revised security update.

If you still can't download directly from the camera, it's certainly the next choice.

As a matter of interest, does the camera icon appear on the desktop?

Have you tried double clicking on that then simply dragging the photos to a folder on the Mac?

If the software you're using is Nikon's, have you tried using the built-in Image Capture app?

What Coolpix model number do you have?