Yes! Aside from forcing the infringer to stop, you may have claims for statutory damages, in addition to damages for lost profits, and you may also make claim for wilful infringement. Take all your facts and communications to a lawyer for review. And don't delay!
My colleague's enthousiasm for your potential claim needs to be tempered by the fact that if you did not register the copyright in your computer program before the infringement occurred then you are NOT entitled to statutory damages or a refund of your attorneys' fees to enforce the copyright. And the fact that proving your "actual" damages is often a difficult evidentiary burden, is often difficult for individual copyright owners to show that those damages are not "speculative" and is costly, time-consuming and disruptive if the evidence shows different licensing fees are being charged to different licensees [if, indeed, the copyright is licensed at all].
So, yes, you MAY have options. But if you don't have a pre-infringement copyright registration then no copyright attorney will assist you on a contingency fee basis. Good luck.
The above is general information ONLY and is not legal advice, does not form an attorney-client relationship, and should NOT be relied upon to take or refrain from taking any action. I am not your attorney. You should seek the advice of competent counsel before taking any action related to your inquiry.
If you are looking to stand on principles, you can check the local law schools in your area and see if any have an IP law clinic. It is possible you might get interest of a professor who might have some ideas for enforcing your rights.
You may also find the DMCA (Copyright Act) Take Down Notice mechanism useful in this situation as well.
Here is a link to some onfo on that as well (just note that I cannot guarantee accuracy of this info): http://rising.blackstar.com/how-to-send-a-dmca-takedown-notice.html
Most of us here, including myself, offer a free phone consult.
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The first question here is going to be whether or not you registered your copyright; if you didn't, the best you can hope for is a law school or legal aid clinic or some other entity willing to take your case on pro bono. You can also issue a DMCA takedown notice, as another attorney mentioned, to bolster your position if they decline to remove the infringing material - but that's really only going to improve your position as regards the sites, not the original infringer.
Speak to a local IP attorney; he or she should be able to help you understand your options and what resources are available in your community to assist you in enforcing your rights as a creator.
No information you obtain from this answer is legal advice, nor is it intended to be. You should consult an attorney for individualized advice regarding your situation. No attorney-client relationship is formed by my responding to your question.