Can anyone recommend any software that can be used to combat software piracy?

License keys, online product validation and server-driven content. Oh and code obfuscation.

Wrong! Give users product for free to create an ecosystem. Create it to be hard to use without proper documentation, online services, hotline, training courses etc. See the biggest ad seller on the NET, growing up exactly on this principle, and compare it with keys-licenses-online_checking approach of old times players...

Create it to be hard to use without proper documentation, online services, hotline, training courses etc

Wouldn't that create very narrow customer base?

here is an anti-piracy software solution. www.cybersurelock.net