Trusted Child Care
Trusted is the fastest and easiest way for parents to find an experienced and vetted caregiver for their children. Using the app, you can book a caregiver with as little as 2 hours notice and check in on the booking via the app.
Besides having a long roster of back up sitters with flexible schedules, one thing I have used a few times in the past is the site Trusted. It's an app/nanny service. They can help you find someone last minute even. In terms of pick up and nanny service there is Kango (http://www.kangoapp.co/) but I haven't personally tried that.