How do I convert MP4 file to AVI or MOV using MacBook Pro (2010)

I am 10.6.4 new user on a new MacBook Pro. This is my first Mac computer.

I want to convert a MP4 video file to AVI or MOV file type. How would I do this on my new Mac? Documentation says I have Quicktime X, but I cannot find Quicktime X on my system. When I try to load Quicktime 7 Pro, my system says I have Quicktime X and cannot load Pro. Apple websites say Pro version will allow me to convert the MP4 files. Anyone have any experience or ideas on what I should do? How do I find Quicktime X? Will it do the conversion for me? Thanks