Hello wanderer,
Patrick's reply (Paddy 199) is very good. If you PM me with your e-mail address I will e-mail you back the Irish VAT guide 2008 (still the latest version available). Suggest you refer to chapter 5, paragraph 11, since that relates specifically to distance sales. If you review appendix J as mentioned in 5.11 it will show you the VAT thresholds for every EU member state upon which you would need to register for VAT in that jurisdiction.
Best regards,
Rudolf289