Also ph33r, ph34r, ph33|2, phj33r, and pheer. Used in the same way that you "fear god". It's a respectful reverance. Also in interjection used when you find somthing extremely desireable or cool.

Examples:

hax0r: dood, i just rooted www.slashdot.org!
llama: whoa, i ph33r j00r mad leet skilletz!