I read some installation instructions for installing Mercurial and checking out the sources. I got more and more confused - and I just tried it out. It turned out to be much easier, than expected. You just have to dowload the mercurial binaries, and execute the installation package (this is all you need for start). On Windows (Vista) it takes about 2 minutes. You don't even have to restart your machine (which is remarkable). Then restart Netbeans 6.1 (in case it is already running), go to Menu "Mercurial" -> "Clone Other". You will be asked for the Repository URL. Use this: http://hg.netbeans.org/main to download Netbeans sources. It will take some time to clone the repo. In my case it took about 40 minutes over slow DSL line. After this you will be asked to open 899 projects (it's a good performance test for netbeans). The whole repo is 1.5 GB big, it contains 167.269 files.