Control 220V AC line using MCU
The best solution for an incandescent lamp is a SSR (Solid State Relay) with zero-crossing detection. (Zero-crossing switching increases the bulb's life.) An SSR module is the most convenient, but they're not cheap. If price is an issue you can better build the SSR from discrete components. Below is an example using the MOC3041 as opto-triac.



edit
Despite Leon's comment this is an inexpensive solution. In this thread I calculated the cost as 2.10 euros; an electromechanical relay (+ transistor, diode, ...) often costs more.