There are some very broad range plans and designs, but no schedule has been set. Currently, the quickest estimate of *any* manned mission to Mars is at least 30 years from now.
The most favored mission design is a very long-range one, lasting 18 to 24 months. As Earth and Mars near opposition, a spacecraft assembled in orbit would fire it's engines for Mars. It would likely take 3 to 4 months until arrival.
At Mars, they would have between 2 and 4 landers - which they'd use one at a time. If one was damaged on landing or was unable to take off, one of the others would be used as a rescue vehicle. If the first 3 operated flawlessly, then they may risk landing the 4th without the option of a rescue.
After 6 to 10 months in orbit about Mars, and spending up to 30 days on the surface at a time, the last lander would dock with the main craft, and then it would leave Mars for Earth, arriving about 20 months later.
This isn't the only mission option, but it was being looked at very carefully about 6 years ago. Currently... everything with "manned" in the title is shelved.