I recently purchased 2 flurescent ceiling lights to install where there have been none. I also installed a new wall switch wired from a baseboard outlet. My problem is that when the light is switched on it throws the circuit breaker. I've checked my wiring (bl. To bl. wh. To wh. and ground to ground) and it all looks good. Also, I have reset the breaker with the switch on and the lights come on. When I turn the switch off and turn it back on the breaker goes again. Any ideas what I'm doing wrong?

I recently purchased 2 flurescent ceiling lights to install where there have been none. I also installed a new wall switch wired from a baseboard outlet. My problem is that when the light is switched on it throws the circuit breaker. I've checked my wiring (bl. to bl., wh. to wh., and ground to ground) and it all looks good. Also, I have reset the breaker with the switch on and the lights come on. When I turn the switch off and turn it back on the breaker goes again. Any ideas what I'm doing wrong?
Most probably you are not doing anything wrong. The problem may be related to earth leak inside the fluorescent ceiling lights.
To check your wiring :
Switch off the light switch. Switch off the breaker.
If the ceiling lights are mounted to anything metal, de-install them but keep them hanging free in the ceiling - wired up, except for the earth wiring. If not mounted to metal, just disconnect the earth wires from each ceiling light.
Switch on the breaker. Switch on the lights.
If the problem is now solved, one or both ceiling lights have an earth leak.
If the ceiling light do not work or the breaker trips, the problem is in the wiring of the light fittings. In that case switch off, and look for the fault. An earth wire may have been switched with a neutral wire.
If the problem is in light fittings :
Switch off lights.
Reconnect the earth wire to one unit. Switch the lights on.
If the breaker trips, the ceiling light with the earth wire has an earth leak problem. If it does not trip, this ceiling light is OK.
Switch off lights.
Remove the faulty ceiling light for repair - if the unit showed faulty.
Reconnect the earth wire to the second unit. Switch the lights on.
If the breaker trips, the second ceiling light has an earth leak problem.
Switch off lights.
Remove the faulty ceiling light for repair.
.
Always be careful please during reconnecting : never touch the ceiling lights when they are powered.
.
Return one or more faulty light fittings to the supplier, and explain what the problem is.
;)

Ezneil, you had a switch loop somewhere and by wiring everything color for color you now have created a dead short by flipping the switch.

What does this mean, exactly:

I also installed a new wall switch wired from a baseboard outlet.

What wires do you have connected to what, in EVERY box?

No, not fireworks, but:

My problem is that when the light is switched on it throws the circuit breaker.

Turn off power, Disconnect wires going to first light fixture, turn power and switch back on, If it doesn't trip, short is in fixtures or associated wiring, if it still trips, short is from switch to light fixture.
If Romex, a staple can short between Hot and neutral or hot and ground.