Raw image viewing on mac OS X 10.6.8

Hi

I am a new mac user, i am a photographer and have a canon EOS 550D.

I shot a wedding yesterday in raw, however i cannot seem to view them on my mac and i dont know why. The computer lets me upload them from the memory card and i have them saved to my desktop, however when i try to open them to view them my mac automatically opens up photoshop ( I have CS5 version ) and it then says i cannot view them because they are raw files and i do not have the right software installed?

Can anyone please tell me where i am going wrong?

Thank you very much, any help is much appreciated

Lucy