So i'm doing my routine check-up on Google Webmaster's inbound links, and see that someone has completely word for word plagarized FIVE of my articles, and published them in her own name on various article submission sites.
I guess amid feelings of being intellectually violated, at least the inbound links to my website were kept intact.
I've had this happen and thankfully the person concerned removed the text when I confronted them.
I was talking about this with someone on another forum who is in a similar situation to you (it was images though) and who asked the offender politely only to have a torrent of what I can only call "madness" thrown back at them. My personal view nowadays is that it's better to go in hard (tough, legalese talk although obviously polite) and if the offender backs down and removes the content - then ease off. Leave them in no doubt that you won't back down.