Visa Requirements?!

Here is the advice on the Irish Citizens Information site for non-EEA visitors:

"Visit/holiday visas are only granted for short term stays and never exceed 90 days. It is not possible to extend your stay beyond 90 days. You must leave the State on or before the date which has been stamped on your passport by the Immigration Officer when you entered."

For longer than this, you will need a 'D' visa. There is information on the Irish Naturalisation and Immigration website. Also note that if you leave Ireland and then return (even if only to Northern Ireland) you need a re-entry visa. You will need to research this very carefully.

Hi. :)

I have a follow up question for you: What if you're from a country from Schedule 1, like the USA, that doesn't need a visa to enter Ireland? Can you still only stay 90 days? And, if you wanted to stay longer, would you still need to apply for a "D" visa?

Yes - from any country outside the EEA (Europe) you only have 90 days. Longer and you will need to research what is required for your situation.
If anyone reading this has experience of staying longer, with official approval, please share your knowledge and experience!

and what's about others official documents and "papers" ? (insurances...) coming from European Union ? (France)

There is information about entry requirements in the FAQ (Frequently Asked Questions) section of the site www.wwoof.ie/faq

All WWOOFers need insurance. There is a special insurance policy available from OVEuropa. Simple health insurance is not enough - you need to be covered for other events.