I went back to work 4 years ago part time and everyone knew me from before so there was nothing to discuss. I did not put my stay at home job in my resume but would add it to a cover letter. If you want to add it to the resume, perhaps a simpler variation of this one: I am what is commonly referred to as a Domestic Engineer. I handle all responsibilities associated with a home based, not- for- profit domestic social experiment (NPDSE). In this capacity, I handle all of the bookkeeping. I also manage the complaint department, in which I moderate all disputes and grievances between 2 or more parties with the goal of speedy and fair resolution. This is a job in which I am on-call 24 hours a day, 7 days a week, even while on vacation (I also serve as travel agent for the NPDSE). I schedule events, fund raisers, handle ALL incoming calls, insurance claims, appointments, utilities, and mortgage payments. I have been on call when the NPDSE requires an organic gardener, nutritionist, landscaper, and/or home renovator. When these responsibilities fall outside the scope of my physical abilities, I co-ordinate and subcontract them. When I am not being a life coach, a medic, a personal assistant, and the operator of a crisis management hotline, I am a motivational speaker. I have encouraged people to do their personal best, and make good choices. I have lectured to small unappreciative audiences in locations all over North America. I got this from http://thisgoesto11.blogspot.com/2008/07/resume-for-stay-...
But in all seriousness, if they ask about the gap let them know what you did, but I wouldn't make a big issue about it. Stick to assessing if the job is a good fit for you and them, ask questions about why the job is available and if you can speak to someone doing that task now, what the career growth potential is, if there is travel, etc. the stuff that is important to you. Good luck!