OK
Make 8drones then get the overlord crankin' 9 drone make an extractor and put for drones on it as son as its done 11 drone make a pool and once your pool is done morph to a hatchery (have a creep colony made as soon as your pool is up if your against zerg) if against toss make two sunken when your lair is morphing. Now make a den about half way into the lair process. as soon as your lairs out upgrae lurker. then make another overlord and 4 hydra. As soon as lurkers are reaserched morph the hydras and then send them into your opponents base.

NOW! this is important depending on what they have. Generaly against a zerg player he will have zerglings at his choke and a couple sunkens. if you are against a zerg make your spire after you have researched lurker. that way when your lurkers come into his base he will utimatley send an overlord to spot the burrowed fiends -scourge any overlord thats close to your lurker and then move straight to his mineral line if he has a sunken there try to move to a spot where the sunken can hit your lurker -just keep scourging his overlord untill then -from here your opponent will be very pressured into wanting to kill your lurkers you can expand with a single lurker for defense and a couple scourges. If you play your cards right you can clean him up with the lurkers there or expand and make mass mutas or hydras -whoteva -its a good strat that i made up and It has worked for me on many many occasions.

Now against the toss!
A protoss generally will pump the zelz at the beginning -this is good you can do the build that i had above and and move your lurkers to his mineral line -if he has too many cannons -make sure what building he has -if any after his cyb core -generally its a robo core and obs -or templar Archives =( I like to deny protoss expansions with lurkers camp them outside his base with an overlord an a couple scourges looking for observers -now make a hatchery at his natural and pump sunken colonies there so if he tries to exit or kill your hatchery he will loose mass troops to the lurkers and sunkens -make sure you kill his obs asap with the scourges. From there expand at his natural and maybe somwhere else and constantly patrol the map for him expading I generally starve a protoss player of his need for minerals then attack -I'll always make queens with blings if he has templars -mutas and guards if he has reavers and hydras if he makes dt and corsair. This is a fun way to defeat your opponent -but i must warn you you have to be a very good macro'er if you want to do this strat -have fun!

CreepColony's Opinion: Scourges aren't my best choice against air; mutalisks and devourers are much better.