Golden Tee Golf (GTG) is an old 3D golf game created by Incredible Technologies back in -98, featuring Peter Jacobsen.
More, in-depth info can be read here.

So, how do we play this online? First of all, you have to join a league.
The biggest out there is Cases Ladder, and can be found here, but there are other leagues to play on.
MyLeague offers a few different GTG leagues, and it's also the home of GTG OldTimers, which can be found here.
Click here to see a complete list.

Remember, not all leagues has the same rules nor share the same ideology, so be sure to read the rules
for the specific league you're about to join.

Have fun and good luck!