Welcome to the Tahoe project, a secure, decentralized, fault-tolerant filesystem. About Tahoe.
This procedure has been verified to work on Windows, Cygwin, Mac, Linux, Solaris, FreeBSD, OpenBSD, and NetBSD. It's likely to work on other platforms. If you have trouble with this install process, please write to the tahoe-dev mailing list, where friendly hackers will help you out.
Check if you already have an adequate version of Python installed by running python -V. Python v2.4 (v2.4.2 or greater), Python v2.5 or Python v2.6 will work. Python v3 does not work. If you don't have one of these versions of Python installed, then follow the instructions on the Python download page to download and install Python v2.5.
(If installing on Windows, you now need to manually install the pywin32 package -- see "More Details" below.)
Download the 1.5.0 release zip file:
http://allmydata.org/source/tahoe/releases/allmydata-tahoe-1.5.0.zip
Unpack the zip file and cd into the top-level directory.
Run python setup.py build to install the tahoe executable into a subdirectory of the current directory named bin.
(Optionally run python setup.py test to verify that it passes all of its self-tests.)
Run bin/tahoe --version to verify that the executable tool prints out the right version number.
Now you have the Tahoe source code installed and are ready to use it to form a decentralized filesystem. The tahoe executable in the bin directory can configure and launch your Tahoe nodes. See running.html for instructions on how to do that.
For more details, including platform-specific hints for Debian, Windows, and Mac systems, please see the InstallDetails wiki page. If you are running on Windows, you need to manually install "pywin32", as described on that page.