First off, your web site isn't down - but your URL is incorrect :-) Info on Ivy can be found at http://www.tls.cena.fr/products/ivy/.

Personally, my view would be to leave it as it is. It's already a publicly distributed module, just not on CPAN. Having different naming schemes for the CPAN and non-CPAN versions will probably cause more problems than it will solve if people are already using Ivy.pm outside of your environment. It looks like you have documentation already written with the existing namespace in mind, and changing it all at this late date is probably more effort than it's worth.

You might want to join the module-authors@perl.org mailing list and ask the question there, where naming issues are often discussed.