Driving a large mosfet directly from any micro is a bad idea.

The gate capacitance will take a while to charge, since the on resistance of the fets in the micro is significant (>10-100 ohms)

Use a driver like the Micrel MIC4429.
I'm using this between an AVR and a TO-220 mosfet to switch power at 500kHz.
The output rise and fall times are impressive, and the FET is staying nice and cold.

A kludge driver like a pnp with pulldown, driven by an NPN can work, but the turn on time won't be wonderful, and the turn off will be worse, and it will get fairly hot and waste power.

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