Pingbacks are bad. However the whole idea of pingbacks is great.
Unfortunately there are far too many scammers, spammers and scraping merchants out there who abuse pingbacks.
If your only getting a few. Check the webpage or site that is doing the pingback, and if it's a good page/site with clean content on it. Accept the pingback. If it's just some spammer who is after ripping your content don't.
Best way IMO as I've been told is to just ignore them.