The Kazaa peer-to-peer (P2P) file sharing software is now the most popular free program on the internet, according to its developer, Sharman Networks.

Reuters reports that the company expects the P2P site to hit over 230 million downloads today, which would inch it past the current most popular program, ICQ instant messaging.

Kazaa has been receiving an average of 366,000 downloads per day, whereas the ICQ application has been receiving an average of 50,000 downloads per day, as measured by Download.com.

Kazaa's growing popularity will anger the music industry, which is continuing its legal battles against P2P sites and its attempts to popularise the emerging commercial online music sites run by companies such as OD2.

Although the recording industry has seen some major successes in the courts in this battle, they suffered a setback in April when a US federal judge ruled that song-swap networks Grokster and Morpheus should not be shut since they did not control what is traded on them.

Kazaa, which also distributes movies, games and software, is itself currently involved in a legal battle with the recording industry.