Any one know where to get some of these?

I am looking for a couple of icons like these:
http://www.templatemonster.com/lib_index.php?cat=2&subcat=25

I can easily do them myself but I need to put together an emergency breeze presentation and am in need of some cool vector icons like now. No time to make them from scratch. Anyone know a site where I can get some for free? I just need a few, like a icon representing a user, user group, internet cloud, and data security maybe a lock or something.