Girl Talk has never had a lawsuit against him, but hip-hop artists have:
http://www.nytimes.com/2008/08/07/arts/music/07girl.html
"In legal terms a musician who uses parts of other compositions creates what copyright law calls a derivative work, so the permission of the original song’s writer or current copyright holder is needed. Artists who sample a recording also need permission from the owner, in most cases the record label. Hip-hop artists who don’t get that permission have been sued, often successfully.
Mr. Gillis says his samples fall under fair use, which provides an exemption to copyright law under certain circumstances. Fair use allows book reviewers to quote from novels or online music reviewers to use short clips of songs. Because his samples are short, and his music sounds so little like the songs he takes from that it is unlikely to affect their sales, Mr. Gillis contends he should be:covered under fair use.
He said he had never been threatened with a lawsuit, although both iTunes and a CD distributor stopped carrying his last album, “Night Ripper,†because of legal concerns. (It had sold 20,000 copies before then, according to Nielsen SoundScan.) It may not be in the interests of labels or artists to sue Mr. Gillis, because such a move would risk a precedent-setting judgment in his favor, not to mention incur bad publicity.
Fair use has become important to the thinking of legal scholars, sometimes called the “copyleft,†who argue that copyright law has grown so restrictive that it impedes creativity. And it has become enough of an issue that Mr. Gillis’s congressman, Representative Mike Doyle, Democrat of Pennsylvania, spoke on his behalf during a hearing on the future of radio."
