I'm going at the end of August. I have reserved a car and driver to take me from Delhi to Agra, from Agra to Jaipur and from Jaipur to Delhi. My intinerary says that the drive from Delhi to Agra takes 4 hours but I assume that there is extra time built into that. I'm staying at the Mughai Sheraton in Agra, which looks nice and comes recommended by my travel agent, although she says it doesn't have a lot of local flavor.
I don't think August is the best time to go, but I am spending some time in the mountains so the winter wouldn't be practical.