There is a reason that companies don't just paint them
but slow heating will bond the paint and plastic a little better than clear coat alone (will not last forever though)

There is also special paint MADE (Krylon Fusion) to bond to plastic, but if not, see below:

Some ideas to get better bonding with regular oil based paint:

Clean the surface THROUGHLY!  Hot soapy water is suitable for this task.  You do not necessarily have to use boiling water (remember that plastics will warp if heated excessively), but definitely used the hottest water you can work with. Also, it's a good idea to use Dawn dishwashing detergent, since it has an anti oil agent (5 mL/L).  This keeps the pain from beading up on you, which means you're not going to get anywhere.  You'll get small pits where there is no paint if the surface is oily, and it looks horrible.  Wash thoroughly, and use a small toothbrush to get into vent areas, and any other crevices. When you are satisfied, rinse in equally hot water, and towel dry with soft lint free cloth.

THE PAINT: Flats dry much more quickly, and are quite forgiving, and; if you plan on COATING with Poly or Clearcoat, you can use a flat color.   Glossy paints are harder to work with on plastics, and tend to run and bead up more on plastic.  You can use regular Krylon paint if you can't find FUSION.  Do not use ANY metal paints, they contain harsh solvents. 

HEAT IT UP: Place your spray can in a hot water stream or in a pot of hot water; to heat it up. Don't exceed 120 degrees, but get close. The reason behind this is that oil based paints mist more finely when heated up, and will give a finer, more even, and smoother coat. They also dry more quickly this way. Once you are satisfied that the can is hot enough, it's time to paint.

Clear the nozzle with a few quick squirts. Then, point the nozzle of the can directly at your target, and with a flat even motion, apply the paint in short bursts, sweeping the can back and forth across the surface. Do not use a steady spray, because you will lay down too much paint, and this causes drips. Only spray enough to cover the item. Let it sit for about 10 minutes (preferably in sunlight, or under a warm lamp in a well ventilated area). Apply around 2 to 3 coats. Do not apply the paint too heavily, or it will flake and crack sooner. After about 25 hours, you can handle the shell. Take a dry paper towel and vigorously rub the panel to buff off any excess paint. Then, a warm wet towel should be used to clean off any paint particles that aren't adhered to the shell that well. When the shell dries, then you can POLY or Clear Coat, using the same spray methods as mentioned above.

The PS3 shell is already SMOOTH as can be, to getting paint to stick is going to be a problem, unless you want to sand the whole thing first.

wow  you could easily make a way better looking console than Microsoft.  Nice job.

That 360 looks awesome