For Spouses of Irish Citizens, the spousal visas are usually quoted as being handled within 6 months.
What lucidj is referring to is the permission to remain. That comes after the Visa, the visa is permission to enter the country for a period of up to 90 days, the permission to remain comes after. The permission to remain is easy if your spouse comes here on a Join Spouse (Long Stay) visa, don't worry about that just yet.
The details for the visa are here with requirements, how to apply etc. is all here.
http://www.inis.gov.ie/en/INIS/Pages/Join%20Family
After the visa (which is a long-stay visa) is granted and they travel to Ireland, your spouse will get a stamp in the airport that allows them to stay up to 90 days. Then during that 90 day period, the two of you go to your local immigration officer with your passports, marriage certificate and proof of a joint address. Then your spouse should get Stamp 4 permission to remain as the Spouse of an Irish Citizen for 3 years.
Have a look here, note that it's the first method mentioned there that'll apply to you, assuming you go down the road of a Spousal Visa.
http://www.inis.gov.ie/en/inis/pages/wp07000024
