Its pretty easy to win.
Heres a quick build guide.
1) Make spawning pool
2) produce ONE zerg worker
3) Rush with a 3zergling rush
4) Make a refinery and get 3workers on it ASAP
4) Make a overlord, then worker, then queen.
5) Harass with your zerglings for around 15seconds
6) Make a baneling next and produce 7zerglings
7) Get as many banelings within 30seconds and send them to kill the terran.
And the time the first rush comes they wont be able to do a complete wall off.