Mosfet drivers are usually integrated circuits. Fairchild is one company that produces them. I think also Infineon and maybe TI and Onsemi have them. Please check their web sites for information on their drivers and how to use them.

There must be  top and bottom MOSFET drivers. The top one is more complicated because the source of the MOSFET is not at the ground. Depending on how high is your H-bridge voltage and driving requirements for your MOSFET (their capacitance, threshold, switching speed)  you can find some driver ICs or other solutions ( optocoupler  based, DC/DC based etc.)

You can use IC555 as monostable driver or micro-controller to generate the frequency to on and off the MOSFET and so frequency of  the inverter.