If you check out
www.entemp.ie (The Dept of Enterprise, Trade & Employment) DETE they should be able to give you the rules/regulations about a non-EU national setting up a business in Ireland.
I don't have any first-hand info on a non-EU students who have attended Irish colleges/universities setting up a business here, but I know that any time spent as a student in Ireland cannot be used as fufilling the 'reckonable residence' requirement when applying for Irish citizenship. I'm not sure if being here on a student visa will make it harder for you.
Check out the DETE first & see what they say. If you're in Dublin, they are located across from the National Library/Museum on Kildare Street.
maria
