Who is going to play in Super bowl 2018:
Both AFC and NFC conference champions are eligible to play Super bowl.
So, this year 2018 AFC chmapion Philadelphia Eagles and NFC champion New England Patriots won the conference championships and will eligible to play the 2018 Super bowl.

Play: Philadelphia Eagles vs New England Patriots Super Bowl 2018
Date: Sunday, February 4, 2018
Time: 6:30 PM ET
Official Broadcaster: NBC(nationwide)
Playing location: U.S. Bank Stadium, Minneapolis

Where to watch Super bowl 2018 live online:
You can watch the games on NBC nationally. They will telecast and cover the game of superbowl sunday on Feb 4, 2018.
Other than that NFLStreaming.Net will stream the 2018 superbowl game online.

You can watch super bowl 2018 live stream from here

From Super Bowl Statistics:
New England Patriots has won 5 times and 10 times appearance of Super bowl until 2018, which is the most winning team ever in NFL history.Current 2017 Super bowl winner is New England Patriots, which is their a strong point of next fight.

On the other hand, Philadelphia Eagles has no super bowl winning record with 3 appearance of Super bowl until 2018.

You need to wait till February 4, 2018 to watch the big fight of Eagles vs Patriots.