Im bout to change my radiator fluid and the manual says that I'm suppose to open the air bleed valve on top of the thermostat housing but I can't see anything that looks like a valve?
anyone??

it looks more like a grease fitting than a valve. Fill radiator and overflow. Start car, turn bleeder valve counter clock wise, rev the motor (a little) manually turn the throttle body, or have friend give it a little gas. Water will squirt out of bleeder, while it's squirting out, tighten the bleeder. All air is gone.

http://img.photobucket.com/albums/v473/CivicSpoon/coolantbleeder.gif
What you should do it get a clear hose that fits snugly over the nipple on the bleeder screw, and a glass jar. Put the hose on the nipple and put the other end into the jar. Fill the jar up with coolant (or even water), just over the hight of the end of the hose. When you loosen the bleeder screw, you'll see bubbles in the coolant (or water) where the air is coming out. When you don't see bubbles anymore, you know you have all the air out of the system. This method also works well with your brakes and clutch.

Personally I've never even used the bleeder screw. I just fill up the radiator all the way, start the car, and let it all drain into the engine. Then keep filling up the radiator as needed, rev the engine a little to let it suck in more coolant (be careful of it shooting out the radiator filler hole). Then I just keep the funnel in the hole with some fluid still in there, let it run for 5-10 minutes, and watch the engine temp every now and then to make sure it's not overheating. After that I put the radiator cap back on, and take it for a drive. But the method with the bleeder screw is probably much better, to make sure all the air is out. So I would try that if you have some hose and a glass jar handy.