There are several possibilities to create swc libraries or assets. You can use embed tags wihing as-classes to force the compiler to include assets directly into your physical swf or you can use the flash IDE to link your assets in the library and publish them afterwards or at least use the flex oem compiler to compile your assets from the console.
There is a catch with all of these possibilities (in my opinion). The flash IDE is not open source, I always forget the syntax of the embed tags and using the console is failure prone.
The SWCGenerator plugin is able to create swc libraries with direct access to Bitmaps, Fonts, Sounds and ByteArrays. You can choose a specific linkage which matches the project structure.
In addition you can choose different unicode ranges and even included characters to make sure not to include unnecessary charsets. Figure 1 shows the add font dialog.

Figure 1: add font dialog
All added assets are stored in a table in a specific eclipse view.

Figure 2: SWCGenerator view
Also it is possible to save and load project settings.
There are two ways to load a project settings file:
1. by a single-click on the file in an eclipse project
2. by a single-click on the "Open Project"-Action in the toolbar.
Installation:
- download SWCGenerator
- put the .jar files in the plugins folder of your eclipse installation directory
- if eclipse is running restart it
- Window -> Show View -> Other -> Addicted2Flash -> SWCGenerator
Please drop me a comment for feature requests or bugs.