Here is how to take advantage on a Protoss in early game being Zerg. Often called a "hydra push", this strategy is one of the most used build against protoss. The key to winning this match up is all about "timing". I've brung to you the best Hydra push I know.

Start to hatch drones and get 8 of them.

Then hatch an overlord, another drone, and as soon as the overlord is done, hatch 3 more drones.

Gather cash with your drones and use one of them (just before the 12th drone finish his morphing) and send him to your expansion to build a hatchery.

Wait until you get 150 and make your spawning pool as soon as possible.

Your almost done with your spawing pool and you have around 250-300$.

Then, make a 3rd hatchery in your main, pump 8-12 zerglings, transfer 4-5 drones to your expand and put a sunken as soon as possible (which means as soon as the creep is there!!!)

You should be 18/18 with around 8 zerglings and 1 sunken. Start your gas (at about 17/18) or so and make an overlord right after.

Keep pumping drones and some zerglings (max 12 zerglings or so; if he tries to zealot rush you, use all your drones and your zerglings + your sunken to survive!) until you get around 25/27. Remember to gather gas as soon as the extractor is completed. Morph an hydralisk den.

While your hydralisk den is morphing, morph 2 overlords and 1-2 additionnal drones. As soon as the hydraliks den is completed, morph non-stop hydralisks while upgrading to fast speed hydralisks.

Once you get about 12 zerglings and 7-8-9 hydralisks (or a little more // less), rush toward protoss base. Never stop pumping hydralisks (you can even rally your hatcheries to his expansion so the hydralisks will be nearer :) Now it's all about micro; back up wounded hydralisks while others in the back attack and do it non-stop until he dies. Be sure to have 1-2 overlords near you since he may try to make some dark templars to keep you from killing him. If you see you're not going to make it, build another hatchery at your natural expand or at your cash expand while making some additionnals drones, get range upgrades (and double evolution maybe) and just overpower him.

Good Luck!!! This is one of my basic strats for zerg! It is great for novices!!! Some experts evan use it, remember to make sure toss dosn't have templars or you will be in a world of hurt. Scout, if he has templars get like 5 queens and brrodling htem then attack, dfilers might help as well! (Plague and Dark Swarm!)

CreepColony's Opinion: I think cannons can stop this pretty easily.