You can set up a care calendar. It's a web-based calendar, so that people who want to help can sign on for the specific day they want to help - that way, you don't get five people on Tuesday, but no one on Wednesday. The person needing help can also say what sort of thing would be helpful on specific days - ie, someone to babysit on Saturday, bring a meal on Wednesdays, don't need anything on Sundays or Fridays, that sort of thing. You can sign up specifically for what you're bringing or doing.
http://www.carecalendar.org/
You can also send out the information on her specific calendar (you need a password to see it) to everyone who wants to help, so it's easier to coordinate with a moms' group and a church or card club or any various groups who all want to help but don't necessarily know each other. We use it often for our moms' group.
Also, we have needed help a couple of times, and I don't know what the weather is like where you are, but our neighbors surprised us by mowing the lawn for us. One less thing on husband's to-do list. And here in Austin, it's already time to start mowing the lawns.