Heres the one I bought for my truck, they have them in all different colors and it has a clear tube on the front that shows the level inside and a petcock on it to open/close it off
http://m.summitracing.com/parts/SUM-G1478or you can grab a clear plastic universal one at the autoparts store for about the same price. Maybe a little uglier.
To install a catch can, you want to run a hose from the overflow nipple on the side of the radiator cap to the catch can. The stock coolant reservoirs on our cars have the hose enter the the top of the reservoir and stick all the way to the bottom. It is important that you make sure the hose either enters the bottom of the catch can and terminates there, or enters the top of the tank and extends to the bottom.
Here is the reasoning in my mind-
the catch can will catch coolant that comes out of the radiator cap. Everytime the engine warms up the coolant will expand some and coolant will need to be released into the catch can to reduce the pressure in the coolant system. This coolant being released will probably be steam, and will just evaporate into the air so the vapors going into the catch can must be immersed in coolant to cool them back into a liquid form. This means the hose must terminate 'underwater'(well undercoolant of course) using one of the two methods in my previous paragraph. Another consideration is that as the engine cools it will draw coolant back into itself because the coolant inside the engine contracts. So once again the end of the overflow hose needs to be immersed at the bottom of the catch can to collect coolant and draw it back into the engine. Lastly, the catch can cannot be airtight and must have a way to dump coolant safely incase it too overflows, so a hose at the top of the carch can that runs under the car away from your paint is needed.
Sorry to add all that in there but I thought it might be helpful to understand the whole process as it plays out in my mind
anyways, hope this all helps you out