I would like to make an inventory of the tools and components aiding the INSPIRE implementation that are available as FOSS. To do so, I have created a wiki page and I encourage your contribution in filling it.
A lot of valuable pieces of software are being developed and they could be ideally reused without reinventing the wheel all the times.
If you are aware of a piece of Free software that responds to this requisite, please add it to the wiki page, with a small description and a link to relevant documentation page, or contact me if you don't have an account for the OSGeo wiki and do not wish to create one.
I think that eventually of this exercise will benefit everyone interested in reusing INSPIRE components.
Thank you for your cooperation!