Welcome to the Haiku WebKit port trac
The repository can be accessed at: http://svn.haiku-os.org/webpositive/webkit/trunk/
For further info visit us on #haiku on freenode or contact us via the mailing list.
Getting & Building
To get the sources just check out the repository mentioned above. The trunk contains a HOWTOBUILD.txt which describes requirements and contains build instructions. It should contain everything you need.