I need to write a lot of class courses presentations to my programming class, and I constantly need to show source code (mainly C
If you are familiar with LaTeX, you should consider using beamer to create your presentation. The wikipedia page has pointers to many tutorials and documents. The user guide is probably the best one I've found.
This can give you all the power of LaTeX for source code snippets (listings package or any other you prefer) along with the rest of the usual features of LaTeX that you're used to. It comes bundled with a score of really nice themes.