Some interesting conversation going on at 11d, Asymmetrical Information, and Raising WEG about the ethics of hiring people to clean your house. Long time readers may remember that I've written quite a bit about housework before.
I don't think there's anything inherent to housecleaning that makes it less moral to hire someone to vacuum your floors or scrub your toilets than to hire someone to mow your lawn or cook dinner. And while Jody's points about the lousy pay that most housecleaners get are totally on target, there's a huge swath of the economy that is just as underpaid, but not as visible. And most of us eat at restaurants without interrogating them as to what the busboys are making.
We don't use a housecleaning service these days (we got a roomba!), but I didn't feel guilty when we did. My personal moral line is that I won't use one of the big services (e.g. Merry Maids, that sort of thing), because too little of the money that you pay goes to the people doing the dirty work. (And Barbara Ehrenreich also convinced me that they don't get the house particularly clean.) I know a few people who have worked as housecleaners, and while it's hard work for not a whole lot of money, the fact that they have multiple employers gives them a degree of independence that lots of low-wage workers don't have. (I do think the DC area is probably atypical, in that the Zoe Baird history has created a real market for housecleaners and nannies who are legally allowed to work and are reporting their income for taxes.)
The Religious Action Center of Reform Judaism has a really good action packet you can download with information about ethical treatment of domestic workers. It talks about things you can do, from treating any workers that you hire justly, to advocating for expansions of various labor standards to include domestic workers. It also includes a link to this article from Lilith magazine that offers a Jewish feminist perspective on hiring a housecleaner.