Can't the xml be edited from the application itself?
I mean we should have a repository with possible cams and a way to browse this repository in fettuccine and add them to the list of saved cams.

The repository packages / webcam can be a simple text file with all info needed and fettuccine should append "downloaded" cams to it's "saved" cams. I am aware of the limitations like: Who can host, how can users contribute with own cams, how to make sure the host just doesn't dissappear?

Another idea: maybe there should be a sort of import dialog/wizard which can append all needed strings to the xml? Like that dialog in HAM, the way you can add repositories HAM.