I have been writing a program (library) in Qt4 and I would like to "release" it somewhere.

The program (library) that I am writing is an EDA (Electronic Design Automation). I am currently writing the back-end part (library in library form) in Qt4 and later I intend to make a front-end part in KDE4. Since I am using Qt4 (and later KDE4) it will work on Linux and Windows (maybe even Mac). At the moment I don't intend to use any external library (except Qt4 and KDE4), so it should be portable...

I have some questions:
1) Which open source license should I use (GPL v2/v3, LGPL...)?
2) Which "software hosting system" should I use (SourceForge, BerliOS...)?

I have no experience with this, so I am asking you guys to guide me.