You didn't state the full load current requirement. However, there are several buck regulator ICs available (NSC, Maxim, Linear) that provide output current on the order of 1A, with few (or no) external components. These switchers typically provide 80% or better efficiency, alleviating the heat sink problems. An example is the National LM2825. It provides 1 Amp with no external components. It has a 24 pin dip package. There are many others available in surface mount packages. Most of these require an external inductor and an external capacitor. Visit the Maxim, National, Linear websites.
Regards,
Jon