We do not handle international tax but we provide varying levels of guidance for certain non-UK taxes. For example, for EU VAT we get provide extensive guidance; for US Sales Tax we can explain how this works and walk you through best practice / point you at relevant providers (have a read of our 1-min primer on Sales Tax for example). If for example you are looking to set up a Bermudan or Cayman entity, unfortunately we cannot help!
A popular jurisdiction we get asked about is if it makes sense to incorporate in Ireland in order to save slightly on Corporation tax. Eventually this level of tax optimisation may make sense for your business, once you have substantial profits. In the earlier stages of running a business, the additional time cost and accounting cost associated with running an Irish company tends to leave less in your pocket and makes this an unattractive option.