There are a number of websites where you can search for jobs in Dublin. It would be a good idea to start your search before you come. You can also start preparing your CV based on job descriptions. Below is a list in no particular order:
One of the most popular job websites in Ireland. Given the cost of posting an advertisement they tend to show medium to high entry positions. Roles for professionals and those in IT. As of writing this they had just over 10,000 jobs listed. They have roughly 2,000 jobs in IT & accounting and finance and 1700 in banking and financial services.
Another popular website with more entry level positions. As of writing this they have just over 2,000 jobs listed for Dublin. They have a wide range of roles. They have roles for waiting staff in a restaurant to .NET developers. Their most popular categories are hotels, restaurants/catering and sales. They also offer work experience / internships. But this isn’t so popular with just 12 roles available as of writing this.
As of writing this they had nearly 20,000 jobs listed for Dublin. They range is very broad. From project managers to cleaners.
Gumtree is a classifieds website. Ads can be posted for free so the quality of jobs varies. Companies post jobs as well as private individuals wanting to hire people. People also use it to advertise their services. As well as jobs they also have a lot of freelance work enabling you to work for yourself. eg web development, cleaning, building, photography etc.
They provide a list of jobs available with startups in Dublin. This can be a great way to get paid while also getting experience working in Ireland. It also provides a useful list of startups in Dublin for you to contact if you want to add experience working in Ireland to your CV.