my questions about VOIP??

I notice that Canadian VOIP carrier Vonage charge service fee similar to cell phone price. Does this mean VOIP call still more expensive than regular land line?
Ans: Yes if you add all the crap that most providers try to sell you it can still be more expensive then a normal phone. For the most part it isn't... I am paying $65 a year for mine here in California but i limit my calls to in state and no international calls.

Can VOIP work without a PC?
Yes but you do need broadband internet (obviously). You can purchase home phones that are developed just for Voip. Providers like Vonage can even sell you their recommended ones.

Does it need a PC turn on 24/7?
Nope... If you buy the VOIP phone all you need is the broadband access and it acts like a normal phone.

Best of luck...
~Cheers

If you use any VOIP phone service, regardless of plan rate, it will have a hit on bandwidth usage in convo, thus affecting torrentz, P2P, or any other I/O app you may have running.
The question is- how much bandwidth do you have to spare, and can your current network handle it (is it modern enough, or configured approprietly?).
...and is your VOIP service configured approprietly?