n00b

i'm looking to convert to linux, but really dont know what i'm doing. i've got an old pentinum 2 pc i'd like to start learning on, and then switch over to my mac. i figure i can just get a distro with an easy install and then just tinker with it, but i'd really like to get to know and understand the workings of linux. does anyone have a book or other source of info they'd recomend?