RSVP by wedding website?

Hi,
Is anyone having guest RSVP to a wedding website? If so which site is good? We will be moving soon and don't want to bother our parents with having responses sent to them so think a website would be best. However we r not sure where to start.

Thanks!!!

we used this option in conjunction with mailed RSVPs and used mywedding.com

the website is super easy