Free Conference Calling -- What!?

So I was trying to figure out how to get my whole family on a conference call this evening (all 8 of us, mostly in different places) and I came across this sweet service PowWow Now. It's 100% free. There is no advertising, no signing up, nothing. You just call the number 1 641 715 3777, come up with a 6 to 9 digit pin, tell you friends and you all call in and enter the pin. Standard call rates apply (which on cells is free) and apparently they make money from some sort of reimbursement they get from telecoms. I'll let you know if it doesn't work or if there are some adverse affects, but trying it out once and cruising the site it seems 100% awesome.