Hi Anne,

I would say that the most important piece of software right now for photography is Lightroom.  It allows you to organize and do certain manipulations on your photographs.  For many photographers it is probably the most important piece of software that they use.  There is a video on the Adobe site that discusses the functionality of Lightroom.

Another Adobe product that is widely used for photography is Photoshop.  The biggest issue with this software, however, is that it's expensive.  A much more reasonably priced option (which has much of the functionality of Photoshop) is Photoshop Elements.  Whatever is not doable in Lightroom can be brought over to Photoshop/Photoshop Elements and done there.

There is a free photo manipulation program by onOne Software which is also very good and can help you with your images.  This is actually a pretty powerful piece of software that for whatever reason onOne has decided to make available for free.  You can download a copy of the software for the MAC from here. Here's another link that will give you some sense of what Perfect Effects is capable of doing.

Hopefully this gives you some idea of what's out there for the MAC.

Ronen