Your library is not ideally portable (see links below). Your media files are just songs/movies. Everything else in the iTunes folder is what gives it the structure you see when you start up iTunes. Copy the entire iTunes folder on the PC to the Mac. If you put it in the default location of Macintosh HD > Users > *User Name* > Music then iTunes will automatically look for it there. (Make sure there isn't anything already in the iTunes folder there that you want to keep since you will be replacing it with the one you are moving.) If you want to put it elsewhere, start iTunes on the Mac with the option/alt key held down and select the iTunes Library.itl file in the moved folder.
What are the iTunes library files? - http://support.apple.com/kb/HT1660
More on iTunes library files and what they do - http://en.wikipedia.org/wiki/ITunes#Media_management
What are all those iTunes files? - http://www.macworld.com/article/139974/2009/04/itunes_files.html
Where are my iTunes files located? - http://support.apple.com/kb/ht1391
iTunes 9 [and later]: Understanding iTunes Media Organization - http://support.apple.com/kb/ht3847 - plus supplemental information about organizing to new structure https://discussions.apple.com/thread/6477809?answerId=26404702022#26404702022
Image of folder structure and explanation of different iTunes versions (turingtest2 post) - https://discussions.apple.com/docs/DOC-7392 - and making an iTunes library portable.
