Yes.
Yes, Jamaicans need a visa to enter Ireland.
yes i need visa to enter Ireland
They will need a visa to enter the United Kingdom in order to enter Northern Ireland.
Yes.
No, Serbian citizens doesn't need visa for Schengen countries, but they need visa for UK and Ireland.
No - you still need a visa to enter the UK !
Usually a separate visa is required to enter England than to enter Ireland, so depending on your own circumstances, if you need a visa to enter Ireland then you will also need another one to enter England. There are proposals from the Irish government to let people who have visas for Britain to enter Ireland without having to get another one for Ireland. As of the time of answering this question (June 2011) this has not been put into place. Even when it does, they doesn't mean that a visa to Ireland will be acceptable to England.
I think so.
Yes, as a Ugandan citizen, you will need a tourist visa to enter Northern Ireland. The UK requires visitors from many countries, including Uganda, to obtain a visa prior to travel. It's advisable to check the official UK government website for the most current visa requirements and application procedures.
Yes, US citizens need a visa to travel to Ireland.
Yes, travelers from the USA need a visa to visit Ireland.
If you are travelling from the USA to Northern Ireland, you need a passport to go there. You probably will also need a visa to enter Northern Ireland but you can find this out if you look up the British government website.