Hi,
What can I say Babar, Peter and Steve, (both Gurus) have explained almost everything. Just few points I would like to mention here are: (and I implemented with my design)

1- You must have an Snubber network across the load, just a 100ohm resistor and a 0.1uf 400v capacitor both in series, but across the load.

2- Zero crossing detector is almost a must while using Triacs, otherwise you should be ready to get harmonics while triacs, switch ON/OFF.

3- There are many way to get zero crossing detection, but the best method so far I experienced is to get direct from Mains. If we take it from after the transformer, you will have phase shift (slightly though) because of transformerming the power through flux. I used a seperate bridge through I drove a optocoupler 4N35 and transistor of 4N35 to interupt pin of CPU.

4- I did not understand the LDR method, why you are using it in your circuit. I think LDR is a slow device for such fast swithing, where you need better shape of wave-forms, all this game depends on wave-form shape. You can drive a triac directly from Optotriac itself. You already using MOC3021, which is a good triac driver. I will send you a circuit for this tomorrow.

5- Now the main topic:
You might be taking the power from the same supply line what you use for Motor load. It is okay but you must do some arrangements in order to eliminate high frequency harmonics generated by inductive load swithing. To do this you can use coils. I mentioned this in my mail to you. You can use a round ferrite core coil with around 30~50 turns and put this into series to your power supply to motor or Fan.
Remember your transformer to micro should be before this coil. and after the coil, line directly goes to Motor, not to any electronics.

Unfortunately I have not drawn my full circuit diagram in presentable form(I am confuse which software to use), but I have in bits and pieces. As soon as my circuit is ready I will forward it to you. But I have complete code done, based on 89C2051. Though it might be confusing to you as there is a keyboard routine and many other fancy work routine.

Rauf