Placing paint pots on airbrush

Hang onto your empty Tamiya bottles. They will screw right onto a Badger air cap. You'll have to shorten the tube some though.

Micromark makes the botle lids with the correct sizes for several paint jars.

http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=60936

But as Trowlfazz said most need to be thinned to use in an airbrush. The only exceptions I know of are colors you use a LOT of. I know some here who paint let's say WWII US Navy AC that thin their Sea Blue in the bottle and spray directly from it since it is a color they use often.

I don't believe there is an adapter for Tamiya paints as they are SO thick usually as to be near impossible to spray directly from the jar......

It could be done with a color bottle attachment. But I won't recommend it because the paint would be too thick (and it's good to keep your paint pots set up for brush painting.)
But try a bottle rather than a cup for a larger source of diluted paint-unless you have a gravity feed airbrush. :-)