Below are some key Open Source projects where BlackBerry participates
BlackBerry is committed to contribute more directly to the WebKit.org community; check out George Staikos post at webkit-dev. Also see WebKit Contributions for BlackBerry Smartphones and WebKit Contributions for BlackBerry PlayBook.
BlackBerry is actively participating in Qt Project. See these two related posts at OpenBBNews: Qt Comes to QNX and Qt Update - 4.8 Binaries and PlayBook QPA Plugin at Gitorious.