I know this is an old question, but I thought I'd add fresh insight and also see if I could get any more answers to this, since I still don't have one I'm satisfied with. There seems to be no other way of getting in touch with OP other than an answer.
There are three services I'm aware of that do this: Gishpuppy (which is what I currently use), Sneakemail (mentioned above) and another service whose name I can't remember. None of these seem reliable enough to trust with such an important function.
However, lately, Gishpuppy's website has been going down, enough to make me feel quite unsettled. While it has still been forwarding email to my private address, I'm worried about what would happen if their service suddenly went down. It would be unfeasible for me to go change my email address for thousands of accounts, many of which I probably won't even remember. So tread with caution. I'm still on the lookout for better alternatives and will keep this answer updated if I find any, I hope you'll do the same.