DH has been a SAHD for 2 years and will likely continue for 2-4 more years.
This wasn't the plan (I was supposed to be the SAHP, but my skills are more marketable in this economy), but it has really turned out okay. It really took lots of adjustment on my part.
One thing I've come to realize is that DH will NEVER do things the way I tell him to, and that's totally okay. His job is to help raise our son and I have to say that I'm really proud of the work he's doing. I really don't think I could have done better.
I expect him to keep our son fed, entertained, and clothed. Anything outside of that is icing on the cake. He takes care of laundry and cleans the kitchen, but I don't expect anything else. Housework is cooperative.
DH has ALWAYS wanted to be a SAHD. He takes DS to playgroup nearly every week and also takes him out nearly every day to walk around town, visit with other kids etc. He does a great job of keeping DS social. To be honest, this is something I absolutely expect of him- staying at home and watching TV or lounging around in pajamas is simply not allowed, and I honestly don't think DS or DH would like doing that, anyway.
DH is also responsible for at-home education. That means that they do lots of reading, counting, and puzzles together. There are no "educational" videos or computer games. My plan was to homeschool DS until we we ready for school, so now that task falls to DH.
I had to help DH understand the idea of complete and balanced meals. DH tends to let our two-year-old dictate meals, and we've had plenty of conversations about how just an apple or crackers is NOT okay for breakfast, even if that's all DS says he wants. DH is now doing a much better job of cooking good meals.

If you are making this transition, remember that the focus is on raising your children, not having a spotless house. In our home, playtime takes precedent over vacuuming.
And dads really DO need some "guy time". DH enjoys playing computer games a few times a week and also hangs out with his friends every couple of weeks. I also try to take DS away for half a day so that DH can just relax.
Like I said, this was a hard adjustment for me, but now I see it as a blessing. When our husbands stay home, we are giving our children an amazing gift that most other kids aren't able to experience.