You can find the following key information for business:
Starting a Business in Ireland
http://www.pointofsinglecontact.ie/Starting-a-Business-in-Ireland/
Tax, Registering a business, Employment Rights, Health and Safety, Establishing a place of business, Closing a Business.
Registering a Business
http://www.pointofsinglecontact.ie/registering-a-business/registering-a-business.html
Companies Registration Office, Procedures for registering your business in Ireland.
Taxation and Social Security
http://www.pointofsinglecontact.ie/tax/
How to register for tax, Revenue online services, Motor Vehicle Registration, Vehicle Registration Tax.
Establishing a Place of Business
Competent Authority, Documentation to be submitted when establishing a place of business
Health and Safety
http://www.pointofsinglecontact.ie/health-and-safety/
Compentent authority, Managing health and safety, Safety statement and risk assessment, Health and Safety Authority.
Employment Rights
http://www.pointofsinglecontact.ie/employment-rights/employment-rights.html
Work Place Relations, Employment law.
Funding / Support
http://www.pointofsinglecontact.ie/online-services-for-business/online-services-for-business.html
Local Enterprise Office, SME online guide to funding supports, Enterprise Ireland, Business Organisations
Licences
Provides Table of licences information.
Closing your Business
http://www.pointofsinglecontact.ie/Irish/D%C3%BAnadh%20Gn%C3%B3/
Administrative procedures involved when closing a business in Ireland.