The DMDirc source code is currently managed using the git version control system. There are instructions for accessing our repositories available to help you. You can also browse the git repository via the web at git.dmdirc.com.
DMDirc is released under the MIT license, a permissive, GPL-compatible open source license.
Finally, you can download an archived copy of the source code via the git web interface. Simply browse to the tag or commit you wish to download and select either a zip, tar.gz or tar.bz2 file. For convenience, the source code for DMDirc 0.6.4 is located here: zip, tar.gz, or tar.bz2.
All of the DMDirc developers hang around in both #DMDirc and #DMDirc.dev on Quakenet (irc.quakenet.org). The developers also publish a development blog where you can keep up with the latest changes we've made, and have a twitter account for shorter updates.