The iUI source code has been mirrored on GitHub for a few months now. Although both GitHub and Google Code support Git, it has become more clear to me that GitHub provides a superior user interface and workflow.
One feature of GitHub that is particularly nice is the network graph visualizer that graphically shows all commits in a network of repositories (e.g. the iUI repo and forks created by users/contributors.) The lack of this feature on Google Code makes it much harder to keep track of what is happening on the various "clone" repositories on Google Code. (Google Code uses the term "clone" repository for what is analogous to a "forked" repository on GitHub.)
The pull request feature of GitHub looks like an improvement over Google Code which has no web user-interface for requesting that code from a clone repository be pulled in to the master. For iUI we have asked that pull requests either be done via the iui-developers Google Group or via the Google Code Issues Database.
The iUI project is ready and I am anxiously awaiting the first pull request on GitHub. After a few successful pulls and merges on GitHub it is likely we'll make GitHub the preferred place for forking, pulling, and merging code changes to iUI. However, we'll continue to use Google Code for it's wiki, issues, and downloads features.