The Daily Business Post has published some of my thoughts on the Irish perspective to the PhoneDog v. Kravitz case, in which a company is suing a former employee for his use of what was a corporate twitter account. PhoneDog primarily seeks a number of injunctions and damages but has raised the issue of ownership in twitter accounts.
In summary, while the issue is somewhat untested in Ireland, employment contracts and policies are likely to be crucial in cases of this nature. There may be something of a split between ownership of a twitter account and ownership of tweets.
Some more views are available in the Irish Independent and WardBlawg.