Essential skills are:
- Knowledge of C++ and experience debugging, testing and profiling C++ applications.
- Experience with Qt. If you're the kind of person who likes delving into the internals of Qt that's even better.
- Solid computer science basics.
Knowledge of any of the following would be particularly useful:
- Model/view frameworks (especially Qt's implementation). An interest in or experience with some of the upcoming Qt technologies (eg. Qt Quick) would also be a plus.
- Databases (in particular, SQLite)
- Search/indexing frameworks (eg. Lucene)
- Scripting languages (eg. Python, Ruby)
- Version control (SVN, git).
- Automated testing tools (eg. QtTest).
- Knowledge of platform-specific APIs such as Cocoa on Mac*.
If you're interested, please get in touch.
* Though Qt abstracts away most platform details, there are times when using native APIs is necessary.