Add in books?

[michael]

Are there any books about writing shared addins?

I've seen and tried examples of adding a button to the office toolbar, but
can't seem to find any examples past this. I'm using visual studio 2003 to
create the addin, staring with the extensibility project wizard. This all
works fine, however when I try to add word and excel interop code, everything
just breaks.

It would be nice to step through the code as well, but this doesn't seem to
work as when I try to debug it just spawns a new instance of visual studio
and ignores any break points.

any advice, links, .. would be helpful.

thanks in advance.